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SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20080422T000000
SUMMARY:Calcul de valeurs de fonctions L complexes I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Karim Belabas ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Karim Belabas
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:179c9d79-a797-4e6c-8548-c90ab61ee5d3
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20080513T000000
SUMMARY:Calcul de valeurs de fonctions L complexes II
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Karim Belabas ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Karim Belabas
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:66f1979f-6dd5-4dad-804e-e6b8bf8e1ca5
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20080529T000000
SUMMARY:Intégration numérique de fonctions analytiques
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pascal Molin ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pascal Molin
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:8b869584-7ab4-4198-8224-65a966835bec
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20080603T000000
SUMMARY:Fractions continues pour la fonction Gamma incomplète I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:d68892c6-24c5-4236-9f10-197853ac3269
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20080610T000000
SUMMARY:Fractions continues pour la fonction Gamma incomplète II
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:38521bb1-c97f-4e12-947c-801c558a1795
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20080930T000000
SUMMARY:Lower bounds for regulators of number fields
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Eduardo Friedman Santiago de Chile ":MAI
LTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Eduardo Friedman Santiago de Chile
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:59700a57-cde3-476e-afc1-c7ef4a93602f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20081007T000000
SUMMARY:Réciprocité cubique et équation de Mordell
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:8a6ede97-be38-424b-bda9-991ad15a5dd2
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20090113T000000
SUMMARY:Barnes' multiple Gamma and zeta functions.and their application to
totally real fields I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Eduardo Friedman Santiago de Chile ":MAI
LTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Eduardo Friedman Santiago de Chile
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a260c4fb-c356-400c-b419-f146a16e5007
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20090120T000000
SUMMARY:Barnes' multiple Gamma and zeta functions.and their application to
totally real fields II
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Eduardo Friedman Santiago de Chile ":MAI
LTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Eduardo Friedman Santiago de Chile
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:445bb72c-9d84-48c8-82c0-3d56a2ff1b3d
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20090122T000000
SUMMARY:Barnes' multiple Gamma and zeta functions.and their application to
totally real fields III
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Eduardo Friedman Santiago de Chile ":MAI
LTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Eduardo Friedman Santiago de Chile
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:2ee7a4be-0cc3-4706-a625-25ea1f89abe0
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20090203T000000
SUMMARY:Barnes' multiple Gamma and zeta functions.and their application to
totally real fields IV
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Eduardo Friedman Santiago de Chile ":MAI
LTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Eduardo Friedman Santiago de Chile
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:4ab8c3cf-bd4c-4096-809e-32857e92ad97
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20090504T000000
SUMMARY:Corps euclidiens: introduction
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean-Paul Cerri ":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean-Paul Cerri
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1ea442c0-3361-4427-9ed3-196d427cecb5
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20090512T000000
SUMMARY:Corps euclidiens: algorithmique. I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean-Paul Cerri ":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean-Paul Cerri
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:86ce4e03-e318-4fab-8f2c-fe36bf6db1d8
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20090519T000000
SUMMARY:Corps euclidiens: algorithmique. II
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean-Paul Cerri ":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean-Paul Cerri
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:587677b3-f63d-4ad0-8bd5-f2eecb17b0c4
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20090619T000000
SUMMARY:Calcul d'isogénies en petite caractéristique
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Luca de Feo Palaiseau ":MAILTO:null@math
.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Luca de Feo Palaiseau
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:01fda33d-c8da-4f7e-87bb-9cb508dbf504
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20090915T000000
SUMMARY:Comptes rendus de SAC et ECC à Calgary
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:d86fa724-af8f-44e3-815c-40f25f52fdb4
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20090922T000000
SUMMARY:Programmer avec la bibliothèque Pari pour les nuls
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Karim Belabas ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Karim Belabas
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:3569cda1-6937-41a5-9962-7fa7b5f3a0d9
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20090929T000000
SUMMARY:The Cohen-Lenstra heuristics for finite Abelian groups.(d'après J
ohannes Lengler)
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Karim Belabas ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Karim Belabas
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:2259f7d4-8d75-4f15-85cb-d315395fc203
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20091006T000000
SUMMARY:An L(1/3) algorithm for ideal class group and regulator computatio
n in.certain number fields
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean-François Biasse ":MAILTO:null@math
.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean-François Biasse
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:b18daa5e-65bb-483b-9106-79903180a09c
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20091103T000000
SUMMARY:Quelques calculs de sommes de Kloosterman et de fonctions L associ
ées.aux variétés de Calabi-Yau. I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:483e7a8b-4c15-44ed-a22f-2776d12a67b4
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20091106T000000
SUMMARY:Invariants de classes (presque) sans réciprocité de Shimura
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:8f15c394-5617-4e81-86b3-2498064f071a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20091110T000000
SUMMARY:Quelques calculs de sommes de Kloosterman et de fonctions L associ
ées.aux variétés de Calabi-Yau. II
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:7f350606-08d2-47c6-9228-b0a460044d6b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20091117T000000
SUMMARY:Abelian surfaces admitting an (l\,l)-endomorphism
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Marco Streng Leiden ":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Marco Streng Leiden
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6557458a-6a06-4711-aaa6-8d53a585016f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20091120T000000
SUMMARY:Calcul des anneaux d'endomorphismes des variétés abéliennes.sur
les corps finis
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Gaëtan Bisson Nancy ":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Gaëtan Bisson Nancy
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ad7683c7-5f67-4e8e-a8cd-912fa0215222
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20091124T000000
SUMMARY:Multiplication complexe de courbes elliptiques:.applications crypt
ologiques
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:2e35271d-fa8d-4a5e-be99-f1a1a461f4f6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20091208T000000
SUMMARY:Multiplication complexe de courbes elliptiques:.construction de co
urbes à petit degré de plongement
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c9586b76-81d1-4ba6-9485-8f4dc5420fca
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20091215T000000
SUMMARY:Multiplication complexe de courbes elliptiques:.algorithmes à bas
e d'approximations flottantes\,.complexité et implantation
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ba402890-f49b-4ec7-b347-35ebbc8ea8b3
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100112T000000
SUMMARY:Méthode des trapèzes et fonctions méromorphes I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pascal Molin ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pascal Molin
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:56c66767-77d3-4b68-b8e1-6e7feaf1a102
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100119T000000
SUMMARY:Méthode des trapèzes et fonctions méromorphes II
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pascal Molin ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pascal Molin
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:724ca05d-6a98-4337-8d68-fa3b70dd3e3f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100126T000000
SUMMARY:Recherche de bons exemples pour la conjecture ABC et la conjecture
.de Hall I (d'apres Elkies et Calvo-Herranz-Saez)
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:7fc73f9e-d07c-4490-a734-dc0a7ac525ea
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100202T000000
SUMMARY:Recherche de bons exemples pour la conjecture ABC et la conjecture
.de Hall II (d'apres Elkies et Calvo-Herranz-Saez)
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:b81dc06d-3e5f-440a-8d85-4fedac81c13e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100211T000000
SUMMARY:Calcul de pairings avec les fonctions thétas
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert Nancy ":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert Nancy
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:aaaf85c5-8978-4d84-aaf7-18b907f0ce32
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100212T000000
SUMMARY:Computing isogenies between abelian varieties
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert Nancy ":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert Nancy
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:f3eb96ac-7c37-4e73-b1ef-b40958599e21
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100216T000000
SUMMARY:Special values of Dirichlet series and Zeta integrals.associated t
o polynomials
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Eduardo Friedman Santiago de Chile ":MAI
LTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Eduardo Friedman Santiago de Chile
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:98131105-7c46-4e38-9602-d04c3f0fb4c7
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100302T000000
SUMMARY:Reduction theory of binary forms over polynomial rings I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pieter Rozenhart ":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pieter Rozenhart
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
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BEGIN:VEVENT
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SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100309T000000
SUMMARY:Reduction theory of binary forms over polynomial rings II
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pieter Rozenhart ":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pieter Rozenhart
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
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BEGIN:VEVENT
UID:c191e12b-ae0d-47f4-93e2-4a770f2cc22a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100316T000000
SUMMARY:Sommes de Gauss\, sommes de Jacobi\, et comptage de points sur des
.hypersurfaces quasi-diagonales I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
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BEGIN:VEVENT
UID:57df36d7-b64b-48d3-bcf9-b332f58b4341
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100323T000000
SUMMARY:Sommes de Gauss\, sommes de Jacobi\, et comptage de points sur des
.hypersurfaces quasi-diagonales II
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:836b8da4-fd92-4181-b43e-c79e03ed15ed
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100330T000000
SUMMARY:Sommes de Gauss\, sommes de Jacobi\, et comptage de points sur des
.hypersurfaces quasi-diagonales III
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
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BEGIN:VEVENT
UID:ef97ce5d-9393-40ca-8a28-53247d018392
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100406T000000
SUMMARY:Comment vérifier si deux représentations galoisiennes ont la.mê
me semi-simplifiée
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Loïc Grenié Bologna ":MAILTO:null@math
.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
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X-SPEAKER:Loïc Grenié Bologna
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
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BEGIN:VEVENT
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SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100518T000000
SUMMARY:The queen of mathematics in communication security
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
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BEGIN:VEVENT
UID:d8ec7e48-b523-45ae-b617-0ba6f9d23b12
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100608T000000
SUMMARY:Algorithme de détermination d'euclidianité et applications I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pierre Lezowski ":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pierre Lezowski
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
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BEGIN:VEVENT
UID:a0e07520-0da9-46cc-9748-e3c76d8514ae
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100615T000000
SUMMARY:Algorithme de détermination d'euclidianité et applications II
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pierre Lezowski ":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pierre Lezowski
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:2e39e06a-eee6-4598-b263-7b32039cdd13
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100909T000000
SUMMARY:Subexponential algorithms for number fields
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean-François Biasse ":MAILTO:null@math
.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean-François Biasse
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:addf76ff-69e4-4f65-94af-9ce06ba67ed6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100917T000000
SUMMARY:Fonctions L de motifs hypergéométriques I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:723dadbe-ac0a-4fce-923c-376886da7caf
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20100924T000000
SUMMARY:An asymptotic analysis of Cuckoo hashing
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Michael Drmota Wien ":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Michael Drmota Wien
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:4bc4c68a-abcc-4e85-8eb2-a68bdb2bbcb1
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101001T000000
SUMMARY:Scalar multiplication on smart cards and side-channel analysis
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Vincent Verneuil ":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Vincent Verneuil
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:dce13f0f-9f42-49d1-8ba7-53bfa56f5f83
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101007T000000
SUMMARY:Peut-on calculer sur ordinateur?
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Paul Zimmermann Nancy ":MAILTO:null@math
.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Paul Zimmermann Nancy
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:cfda9483-8acd-4458-a082-d1609b63574d
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101012T000000
SUMMARY:The security of the discrete logarithm problem (DLP) in the.contex
t of pairings
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Manuel Charlemagne Dublin ":MAILTO:null@
math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Manuel Charlemagne Dublin
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6de36099-7463-46d6-80bc-b0883d6284c8
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101012T000000
SUMMARY:The security of the discrete logarithm problem (DLP) in the.contex
t of pairings
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Manuel Charlemagne Dublin ":MAILTO:null@
math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Manuel Charlemagne Dublin
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a7200a1e-10bb-4970-ad8b-014abcb7d3ac
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101015T000000
SUMMARY:Intégration numérique et calculs de fonctions L
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pascal Molin ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pascal Molin
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a938dbe6-ff10-44cf-a1bc-079a7557004f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101022T000000
SUMMARY:Fonctions L de motifs hypergéométriques II
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1e68df61-cf31-46f9-87ec-c234dad34249
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101119T000000
SUMMARY:Computing quadratic function fields with high 3-rank via cubic fie
ld.tabulation
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pieter Rozenhart ":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pieter Rozenhart
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:03d421ff-6b4b-4f51-bac5-00e55599b106
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101126T000000
SUMMARY:HQFRU HIDXW LODYR LUODE RQQHF OHI
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:54dc3857-8961-4213-961e-4942415480c8
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101126T000000
SUMMARY:HQFRU HIDXW LODYR LUODE RQQHF OHI
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:be141cdb-6e4a-4963-b643-585ce4998fba
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101206T000000
SUMMARY:Calcul de groupes d'inertie
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:9867ed95-f74d-47ae-aaa2-db96954307ec
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101206T000000
SUMMARY:Calcul de groupes d'inertie
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:fe6f3f78-829a-4437-845c-6815ec5b3782
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101207T000000
SUMMARY:Relèvement de représentations avec conditions en p
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Julien Blondeau Besançon ":MAILTO:null@
math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Julien Blondeau Besançon
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:819ca5c6-2ba2-4be7-ab4a-b4256f93bc4a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101207T000000
SUMMARY:Relèvement de représentations avec conditions en p
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Julien Blondeau Besançon ":MAILTO:null@
math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Julien Blondeau Besançon
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:dce5efa1-657d-4bb1-86c7-681f94f0c18e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101207T000000
SUMMARY:Relèvement de représentations avec conditions en p
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Julien Blondeau Besançon ":MAILTO:null@
math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Julien Blondeau Besançon
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6b53694b-a9a1-4ed3-afd3-2458aad7bf83
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101207T000000
SUMMARY:Relèvement de représentations avec conditions en p
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Julien Blondeau Besançon ":MAILTO:null@
math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Julien Blondeau Besançon
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:2cf78c2f-3ee5-4c9e-b9b6-bef9097ec7b9
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101208T000000
SUMMARY:Variétés abéliennes\, fonctions théta\, applications I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:48ee7a9a-a9a2-4b0b-a647-76d1088d0cca
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101208T000000
SUMMARY:Variétés abéliennes\, fonctions théta\, applications I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c5de0488-90bb-4de3-96d6-a818b1405017
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101208T000000
SUMMARY:Variétés abéliennes\, fonctions théta\, applications I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:7c0c2173-8023-401f-bb56-779bdee655ba
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101208T000000
SUMMARY:Variétés abéliennes\, fonctions théta\, applications I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:34b0f28f-a99c-48e4-85d8-2b70e349bc0b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101209T000000
SUMMARY:Points rationnels de courbes modulaires I:.estimations analytiques
en grand niveau
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pierre Parent ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pierre Parent
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:8497d8be-ef31-466d-ba20-da535ab456b8
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101209T000000
SUMMARY:Points rationnels de courbes modulaires I:.estimations analytiques
en grand niveau
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pierre Parent ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pierre Parent
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:99803f82-13dc-4a5e-b08e-3ae22de2ff9c
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101209T000000
SUMMARY:Points rationnels de courbes modulaires I:.estimations analytiques
en grand niveau
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pierre Parent ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pierre Parent
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:68dc6690-b9cb-416d-bf03-b68eb48c88f9
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101209T000000
SUMMARY:Points rationnels de courbes modulaires I:.estimations analytiques
en grand niveau
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pierre Parent ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pierre Parent
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:3c32c41c-171f-4bdc-bde9-78242ca6866a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101210T000000
SUMMARY:Polynômes de classes par restes chinois
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:42a6f9f0-d971-473f-ac2b-19d338f5706c
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101210T000000
SUMMARY:Polynômes de classes par restes chinois
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c02b6307-0160-4f29-a092-d2404e6cdd7e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101210T000000
SUMMARY:Polynômes de classes par restes chinois
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1d1e2a19-8a4f-4142-8d88-b64c9dd996db
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101217T000000
SUMMARY:Scalar multiplication on smart cards and side-channel analysis\, l
e.retour
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Vincent Verneuil ":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Vincent Verneuil
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:29f9c82b-83f0-4ec2-8c02-08ef3e6c7cbf
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20101217T000000
SUMMARY:Scalar multiplication on smart cards and side-channel analysis\, l
e.retour
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Vincent Verneuil ":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Vincent Verneuil
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:8cb30798-ea8a-4a3a-9f54-c6139d975664
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110127T000000
SUMMARY:Calculs rapides modulo un ensemble triangulaire et.applications
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Adrien Poteaux Paris 6 ":MAILTO:null@mat
h.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Adrien Poteaux Paris 6
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:bcfe315c-99bd-463e-8359-2c83a17031be
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110203T000000
SUMMARY:Calcul de points rationnels sur une courbe elliptique par la méth
ode. de Silverman-Cremona-Delaunay.
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:57d32ae4-f328-4906-957c-8692be298431
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110210T000000
SUMMARY:Géométrie des tangentes d'inflexion d'une cubique plane et. les
pseudo-paramétrisations qui s'en déduisent
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean-Marc Couveignes ":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean-Marc Couveignes
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:d212745c-95b7-4c46-97ce-c0dd50a5d6b7
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110217T000000
SUMMARY:Algorithmique pour les jacobiennes de courbes:. algorithmes class
iques et méthodes de Khuri-Maksidi
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Nicolas Mascot ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Nicolas Mascot
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:0082fd9f-e909-4ada-b5a5-a87f159bfe28
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110224T000000
SUMMARY:Couplages sur les courbes d'Edwards et formules d'addition complè
tes
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Christophe Ritzenthaler ":MAILTO:null@ma
th.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Christophe Ritzenthaler
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:47531c2b-21df-434e-aebd-354c142be1fc
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110303T000000
SUMMARY:Factorisation torique des polynômes bivariés
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Martin Weimann ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Martin Weimann
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:bd0c091c-a3cb-4315-86e0-ef2b812f272f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110310T000000
SUMMARY:Termes restes dans le théorème de Davenport-Heilbronn I
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Karim Belabas ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Karim Belabas
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:e8e4d7f3-e658-497b-88c4-43ecf0266d90
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110317T000000
SUMMARY:Termes restes dans le théorème de Davenport-Heilbronn II
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Karim Belabas ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Karim Belabas
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:83ba980a-3189-4495-b1fc-66018d649a73
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110331T000000
SUMMARY:Termes restes dans le théorème de Davenport-Heilbronn III
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Karim Belabas ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Karim Belabas
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:255990ed-9114-47f5-99b9-dfb30c7d2994
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110414T000000
SUMMARY:Attaques par recouvrement et décomposition du logarithme discret
sur. courbes elliptiques.
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Vanessa Vitse Versailles ":MAILTO:null@m
ath.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Vanessa Vitse Versailles
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:cf77e5de-e320-40c2-a21f-af06220ab4f6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110428T000000
SUMMARY:Algorithmique des phi-modules pour les représentations. galoisie
nnes p-adiques
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jérémie Le Borgne Rennes ":MAILTO:null
@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jérémie Le Borgne Rennes
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:d6afa469-fea5-4d36-9946-a86033fe4db6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110505T000000
SUMMARY:L1 a new quasi-linear LLL algorithm
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andy Novocin Lyon ":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andy Novocin Lyon
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1bb40216-9446-44e5-a558-cac79a7e17cd
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110519T000000
SUMMARY:Sur la conjecture de Gross
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Lassina Dembelé Warwick ":MAILTO:null@m
ath.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Lassina Dembelé Warwick
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:07ccf094-d860-4a27-998a-02628215c3db
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110526T000000
SUMMARY:Calcul du groupe de classes et des unités dans les corps de nombr
es
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean-François Biasse Calgary ":MAILTO:n
ull@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean-François Biasse Calgary
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c13cb3ee-8828-4d52-8604-eab8a207fc8d
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110907T000000
SUMMARY:Pairings implementation in the PARI computer algebra system
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jérôme Milan ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jérôme Milan
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:91cddda9-f10a-4626-9d2d-a25fc0ec9e04
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110923T000000
SUMMARY:Paramétrisation des cubiques planes à l'aide d'un radical.cubiqu
e
LOCATION:Salle de Conference
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean-Marc Couveignes ":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean-Marc Couveignes
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:b3db1865-656c-40b5-b668-c69f706d8a97
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110928T150000
SUMMARY:Radical extensions and primitive roots
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Peter Stevenhagen Leiden ":MAILTO:null@m
ath.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Peter Stevenhagen Leiden
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:69b55bab-fc29-4ba3-be14-744f5f521ea9
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20110930T140000
SUMMARY:Couplages optimaux sur variétés abéliennes via les fonctions.th
êta
LOCATION:Salle de conférences
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:9a13f544-f142-47d9-84d6-90078f9fc66b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20111005T150000
SUMMARY:Conjectures\, experiments\, and algorithms concerning the moments.
of L(1/2\,?d)
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Michael Rubinstein Waterloo ":MAILTO:nul
l@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Michael Rubinstein Waterloo
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a7bf90f9-9d65-4039-8b05-430627dd0adf
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20111013T140000
SUMMARY:Computing the image of Galois representations attached to elliptic
curves
LOCATION:Salle de conférences
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Julio Brau ":MAILTO:null@math.u-bordeaux
.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Julio Brau
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a9dc475a-9159-4589-b63d-5967ef8f54c6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20111025T150000
SUMMARY:Développement de Pari/Gp sous Git
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:9da47abc-d631-483a-b698-343fbfc7e6e9
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20111025T150000
SUMMARY:Développement de Pari/Gp sous Git
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ee9c46d2-64df-47eb-9176-a160d8c5814f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20111025T150000
SUMMARY:Développement de Pari/Gp sous Git
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:5f6e4843-172c-4623-ac9a-8e436de8380a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20111025T150000
SUMMARY:Développement de Pari/Gp sous Git
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:42878d59-4c1d-4388-8de4-bff4458fdecf
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20111025T150000
SUMMARY:Développement de Pari/Gp sous Git
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:64008afb-89db-4186-aa41-b2efaacacc41
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20111025T150000
SUMMARY:Développement de Pari/Gp sous Git
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:41f84c59-1969-4677-8b8b-886b62c0a632
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20111025T150000
SUMMARY:Développement de Pari/Gp sous Git
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:41542c81-991c-42f4-ae9e-2b616a874c8d
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20111025T150000
SUMMARY:Développement de Pari/Gp sous Git
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:f0702d5c-cf9e-4ac3-9874-52b7aee67f66
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20111025T150000
SUMMARY:Développement de Pari/Gp sous Git
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:9aaa023b-fb0b-47a6-95fd-15ea7e154ca6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20111025T150000
SUMMARY:Développement de Pari/Gp sous Git
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:e5a35109-b5fa-4156-8097-05414ce665f8
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20111025T150000
SUMMARY:Développement de Pari/Gp sous Git
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a7d7466a-b226-4314-976e-50ad23ab6817
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20111201T140000
SUMMARY:Isomorphic Absolute Galois Groups of Number Fields
LOCATION:Salle de conférences
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Athanasios Angelakis ":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Athanasios Angelakis
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:9ae29632-242c-47dd-bcbe-b3a7dd85b5dd
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20120202T153000
SUMMARY:Square Always Exponentiation
LOCATION:Salle 2
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Vincent Verneuil ":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Vincent Verneuil
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:25e1dc42-b232-46d3-a6c4-7730c5e56877
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20120224T100000
SUMMARY:Logarithmes discrets elliptiques par recouvrement I
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean-Marc Couveignes ":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean-Marc Couveignes
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:fb2984a6-e31d-4df0-99ef-d3d5c17019a0
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20120308T110000
SUMMARY:Logarithmes discrets elliptiques par recouvrement II
LOCATION:Salle 1
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean-Marc Couveignes ":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean-Marc Couveignes
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:3736b7a8-e74a-4b22-aaa4-6b2f4aebe23c
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20120312T110000
SUMMARY:Searching for congruences of Galois representations
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Vasily Golyshev ":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Vasily Golyshev
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:899769a5-135e-4ace-a335-b9658b2fd968
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20120322T133000
SUMMARY:Lacunarité des quotients &eta\;
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:46a54dab-9435-4d7a-a8d2-7eab846abb71
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20120329T133000
SUMMARY:Smaller class invariants for quartic CM-fields
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Marco Streng Warwick ":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Marco Streng Warwick
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:7baca1e8-3cee-458d-9451-82f24bac150e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20120412T133000
SUMMARY:Un algorithme à la Pollard pour le problème du sac à dos
LOCATION:Salle de conférences
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Gaëtan Bisson Sydney ":MAILTO:null@math
.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Gaëtan Bisson Sydney
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:225bd4d1-df92-4e1e-ac5f-2e3aede0fcf1
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20120510T133000
SUMMARY:Polynômes de classes en genre 2 par la méthode des restes chinoi
s
LOCATION:Salle de conférences
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:b60f943a-ec74-4477-851d-4f91a7136380
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20120524T110000
SUMMARY:Corps de quaternions euclidiens
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pierre Lezowski ":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pierre Lezowski
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1dc887c1-6cb4-4be2-b602-f667930c7a2a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20120702T150000
SUMMARY:Values and ideals in combinatorial problems
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bernhard Schmidt Singapore ":MAILTO:null
@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bernhard Schmidt Singapore
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:beb61deb-e3f3-48c1-bfa5-c0df194d3c82
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20120911T100000
SUMMARY:Techniques de criblage pour la factorisation et le calcul de logar
ithmes. discrets
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Enea Milio Montpellier ":MAILTO:null@mat
h.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Enea Milio Montpellier
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:fbe7695c-3a1c-4c9b-80f8-c6b6daea1103
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20120918T100000
SUMMARY:Calcul de résidus de la fonction zeta
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Karim Belabas ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Karim Belabas
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:79f2f31e-d846-456c-b459-adc6136a484f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20120925T100000
SUMMARY:Décompositions en hauteurs locales sur les courbes elliptiques I
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Fabien Pazuki ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Fabien Pazuki
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:53af3a72-3a32-4a72-8d92-99ce6596b963
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20121002T100000
SUMMARY:Décompositions en hauteurs locales sur les courbes elliptiques II
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Fabien Pazuki ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Fabien Pazuki
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:7fbcaccc-e46f-4e3f-b41a-8c8f6fb8a2aa
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20121009T100000
SUMMARY:Packings of bodies in Euclidean space
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Fernando Mario ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Fernando Mario
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:085ef6af-e93f-4a5d-99a9-48ec90f9dddd
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20121016T100000
SUMMARY:Tomographie arithmétique
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Karim Belabas ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Karim Belabas
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:e2cc4137-ce42-4842-aba0-6947f7697fb6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20121023T100000
SUMMARY:Comptage des corps cubiques et quartiques
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ad58e3ba-c4eb-451e-94be-37d34abf494f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20121030T100000
SUMMARY:Towards Quantum-Resistant Cryptosystems from Supersingular Ellipti
c Curve Isogenies
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Luca De Feo ":MAILTO:null@math.u-bordeau
x.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Luca De Feo
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:9b5eb532-2af0-4204-a457-6b4aeefdd300
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20121120T100000
SUMMARY:Comptage de points sur les courbes elliptiques en petite caractér
istique
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert ":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:20226553-4cc8-40d9-a0bf-598d0f4f1bd3
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20121127T100000
SUMMARY:Le calcul des maxima locaux de l'invariant B-M d'un réseau est-il
algorithmique?
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jacques Martinet imb ":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jacques Martinet imb
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:26344453-4802-47a7-b2ad-51ec531d0124
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130108T100000
SUMMARY:Problème de la phase dans le cadre discret
LOCATION:IMB: Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Philippe Jaming imb ":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Philippe Jaming imb
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:4b282b91-f88c-4e04-9aca-f61993f7a56e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130122T100000
SUMMARY:Arithmetic on Jacobians of relative curves
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Hamish Ivey-Law imb ":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Hamish Ivey-Law imb
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:7823ebe4-edbd-4ae6-beb8-04d8554432d4
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130129T100000
SUMMARY:Calcul de représentations galoisiennes modulaires
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Nicolas Mascot imb ":MAILTO:null@math.u-
bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Nicolas Mascot imb
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a238e1e9-a771-4155-8c05-9e1f70009ede
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130205T100000
SUMMARY:Algorithms for isogeny graphs
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Sorina Ionica ENS Paris":MAILTO:null@mat
h.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Sorina Ionica
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:eb530269-bad2-424b-a420-ccc340c543b3
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130219T100000
SUMMARY:A faster pseudo-primality test
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Tony Ezome Université de Masuku ? Franc
eville\, Gabon":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Tony Ezome
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:74aa53d9-00c8-4cf3-9fc4-15afd2b863b1
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130226T100000
SUMMARY:Algorithme diviser pour régner pour les cartes routières
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Marie-Françoise Roy Rennes":MAILTO:null
@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Marie-Françoise Roy
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:980fa067-258b-4f98-98d9-560400b44de2
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130305T093000
SUMMARY:A propos de domination dans les graphes.
LOCATION:IMB: Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Paul Dorbec Labri":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Paul Dorbec
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:b4e58605-c76f-440c-ab92-dc27d4a88c44
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130319T100000
SUMMARY:Systèmes linéaires spéciaux sur courbes et le problème du loga
rithme discret
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Claus Diem Leipzig":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Claus Diem
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:027333eb-d65b-4ea1-8375-6e2c15fea01f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130409T100000
SUMMARY:Groupe de classe d'Arakelov
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pierre Lezowski imb":MAILTO:null@math.u-
bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pierre Lezowski
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ae28f120-297b-4100-b26c-30064ddb13fa
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130416T100000
SUMMARY:Identifying coDes in Evolving grAphs (IDEA).
LOCATION:IMB: Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Ralf Klasing Labri":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Ralf Klasing
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c538c020-23e1-4e3f-ae69-26746cc31ad6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130423T100000
SUMMARY:Calcul de corps de classe de rayon de courbes de genre $g \\neq 0$
.
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pierre Chrétien imb":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pierre Chrétien
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:f452def9-38a2-45ae-9e5c-0978ba3c8037
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130514T100000
SUMMARY:Point Compression for the Trace Zero Variety
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Maike Massierer University of Basel":MAI
LTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Maike Massierer
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:842c63a3-c984-4a12-9694-69583a585b64
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130528T100000
SUMMARY:Exploiting Symmetries in Polyhedral Computations
LOCATION:IMB: Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Achill Schürmann Universität Rostock":
MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Achill Schürmann
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:dbd25be6-a452-4a74-8586-4725b14ec7be
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130611T100000
SUMMARY:A first package for modular forms in Pari/GP
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen imb":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:43d5ac74-76ef-4bca-80e3-38f87265bd57
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130618T100000
SUMMARY:Cone theta functions and what they tell us about the.irrationality
of spherical polytope volumes.
LOCATION:IMB: Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Sinai Robins (Nanyang Technological Univ
ersity (Singapore)) ":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Sinai Robins (Nanyang Technological University (Singapore))
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ce11a2d2-a6d1-4961-a5a8-a0d3508bc5a9
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130910T100000
SUMMARY:An algorithm to enumerate quartic fields\, after Bhargava.
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Friedrich Panitz Paderborn":MAILTO:null@
math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Friedrich Panitz
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:4275a4ce-a84d-4fc7-b60b-3269df3b2c9d
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20130924T100000
SUMMARY:The Riemann-Roch problem for divisors on two classes of surfaces
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Hamish Ivey-Law imb":MAILTO:null@math.u-
bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Hamish Ivey-Law
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:0f3788cf-b55e-42e9-9124-59994d7e162f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20131004T140000
SUMMARY:Polyhedra associated with identifying codes
LOCATION:LaBRI: Salle 178
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Sylvia Bianchi () ":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Sylvia Bianchi ()
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c9107a9b-7c82-46d2-8564-b1dde320f03c
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20131025T140000
SUMMARY:Graphes sur des surfaces et codes quantiques
LOCATION:LaBRI: Salle 178
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Gilles Zémor () ":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Gilles Zémor ()
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a749d17a-22b2-43dc-85b0-3c962da6b8f7
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20131105T100000
SUMMARY:Algorithmes de Voronoi et groupes d'unités
LOCATION:IMB: Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Renaud Coulangeon imb":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Renaud Coulangeon
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:911e8235-cb19-483a-a99c-b0a29005af12
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20131122T130000
SUMMARY:Théorie de Bass-Serre des graphes de groupes et application au ca
lcul de.la présentation du groupe d'unité d'une algèbre semi-simple (1)
.
LOCATION:IMB: Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Renaud Coulangeon imb":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Renaud Coulangeon
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:f365ad0a-af21-4d11-94f4-f000fae0573a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20131122T130000
SUMMARY:Théorie de Bass-Serre des graphes de groupes et application au ca
lcul de.la présentation du groupe d'unité d'une algèbre semi-simple (1)
.
LOCATION:IMB: Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Renaud Coulangeon imb":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Renaud Coulangeon
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:472db9bc-065e-4ee2-928e-167326e0d92a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20131129T130000
SUMMARY:Théorie de Bass-Serre des graphes de groupes et application au ca
lcul de.la présentation du groupe d'unité d'une algèbre semi-simple (2)
.
LOCATION:IMB: Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Renaud Coulangeon imb":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Renaud Coulangeon
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:2638361f-902b-49fb-8300-94b31f1c1a1a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20131210T100000
SUMMARY:Minimums de formes quadratiques
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert imb":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:195f9d39-c4cd-4f62-917b-17d8d1211bda
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140121T100000
SUMMARY:Local-Global for Isogenies on Elliptic Curves
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Barinder Banwait imb":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Barinder Banwait
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:9c34bc1f-4a06-461f-839e-1a37ad0efd8e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140128T100000
SUMMARY:Zeta values\, random matrix theory and Euler-MacLaurin summation
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Hartmut Monien Physikalisches Institut d
er Universität Bonn":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Hartmut Monien
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:48fd7e3d-0c22-41a1-a751-e164f9883bd5
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140130T093000
SUMMARY:Calculating rational coverings for subgroups of ${\\rm PSL}_{2}\\l
eft(\\mathbb{Z}\\right)$ efficiently
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Hartmut Monien Physikalisches Institut d
er Universität Bonn":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Hartmut Monien
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:b46ee924-e291-4f21-8d6f-855cd2bd811b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140204T100000
SUMMARY:Moments des fonctions thêta
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Marc Munsch IMB":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Marc Munsch
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:11414879-f8a2-4e5f-b681-61aabde69ef5
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140220T150000
SUMMARY:Cône de Shintani et degré topologique
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Eduardo Friedman Universidad de Chile":M
AILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Eduardo Friedman
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ba0ef3ef-6ac7-469d-9267-0b0f3ddf1c7f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140304T100000
SUMMARY:Heuristiques sur les variétés abéliennes adaptées à la crypto
graphie à couplage
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="John Boxall Caen":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:John Boxall
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:efda2225-d701-437a-b0a2-dbd4716da38a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140318T100000
SUMMARY:The class number one problem for genus-2 curves
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="P?nar K?l?çer Leiden+IMB":MAILTO:null@m
ath.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:P?nar K?l?çer
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:675d75f5-c7fb-42c1-9678-8241daac122c
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140321T100000
SUMMARY:Arbre bronchique infini et entiers dyadiques
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bertrand Maury Paris-Sud":MAILTO:null@ma
th.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bertrand Maury
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c04fc521-11e0-4970-bdb1-92de07cbeec7
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140324T100000
SUMMARY:Un algorithme quasi-polynomial de calcul de logarithme discret en
petite. caractéristique
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Emmanuel Thomé Nancy":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Emmanuel Thomé
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:f2ca36a8-1c13-41ed-a2b8-04235d58b409
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140401T100000
SUMMARY:Estimations for the Artin conductor
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Amalia Pizarro-Madariaga Valparaíso":MA
ILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Amalia Pizarro-Madariaga
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:146574ac-3845-4c0b-8acb-3b0dd8a9700e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140408T090000
SUMMARY:Visite de la directrice du centre Inria Bordeaux
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Monique Thonnat Inria Bordeaux Sud-Ouest
":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Monique Thonnat
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:244bb9d8-354a-4b48-b0f8-ef774272bd0a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140513T100000
SUMMARY:Numerical recipes for multiprecision computations
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen imb":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:5175887c-5f59-4777-83e2-7cebc0931c82
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140520T100000
SUMMARY:Computing a Velu type formula for rational cyclic isogenies betwee
n.isomorphism classes of Jacobians of genus two curves that are defined ov
er a.finite field.
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Alina Dudeanu EPFL":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Alina Dudeanu
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:df337e68-2b5d-437e-916e-c8f5365dc312
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140603T100000
SUMMARY:On polarised class groups of orders in quartic CM-fields
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Gaetan Bisson University of French Polyn
esia":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Gaetan Bisson
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c6af5496-9b7b-413d-a9cc-1bcf5a5e8314
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140708T110000
SUMMARY:Moduli interpretation of Eisenstein series
LOCATION:Salle 1
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Kamal Khuri Makdisi American University
of Beirut":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Kamal Khuri Makdisi
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:558e5575-a0ba-477a-bf04-9ff50600ec46
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140710T160000
SUMMARY:On divisor group arithmetic for typical divisors on curves
LOCATION:Salle 1
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Kamal Khuri Makdisi American University
of Beirut":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Kamal Khuri Makdisi
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:dbbf8e8d-5e04-4c34-abb7-f64418cc9e80
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140916T100000
SUMMARY:Reliable multiprecision arithmetic for number theory
LOCATION:Salle 385
DESCRIPTION:Many calculations involving real or complex numbers can be don
e provably correctly by combining mathematical error bounds with a rigorou
s error propagation scheme (interval arithmetic or ball arithmetic). An on
going research subject is to develop efficient algorithms and software imp
lementations in this setting.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Fredrik Johansson imb":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Fredrik Johansson
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:80748da4-8dfc-4e45-9d90-c5fed53bd7f8
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140923T110000
SUMMARY:Points CM sur les droites
LOCATION:Salle 385
DESCRIPTION:$\\newcommand{\\C}{{\\mathbb{C}}}\\newcommand{\\Q}{{\\mathbb{Q
}}}\\renewcommand{\\Im}{{\\mathrm{Im}}}$ Let $\\tau$ be an imaginary quadr
atic number with ${\\Im\\tau>0}$ and let $j$ denote the $j$-invariant func
tion. According to the classical theory of Complex Multiplication\, the co
mplex number $j(\\tau)$ is an algebraic integer. A *CM-point* in $\\C^2$
is a point of the form $(j(\\tau_1)\,j(\\tau_2))$\, where both $\\tau_1$ a
nd $\\tau_2$ are imaginary quadratic numbers.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Yuri Bilu and Bill Allombert imb":MAILTO
:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Yuri Bilu and Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:845e4885-e8cb-4318-9f83-5ea090f78e4a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20140930T100000
SUMMARY:An algorithm for computing Hilbert modular varieties
LOCATION:Salle 385
DESCRIPTION:We describe an algorithm for computing an analogue of the modu
lar polynomial for elliptic curves\, for principally polarised (p.p.) abel
ian varieties with real multiplication (RM). Given a p.p. abelian variety
with RM by $\\mathcal{O}_{F}$\, where $\\mathcal{O}_{F}$ is the maximal or
der in a totally real number field $F$\, for any totally positive prime $\
\mu$ in $\\mathcal{O}_{F}$\, one can find a "$\\mu$-isogenous" p.p. abelia
n variety with RM by $\\mathcal{O}_{F}$. We describe an algorithm to compu
te a birational model for an algebraic variety which parametrises $\\mu$-i
sogeny classes of p.p. abelian varieties with RM by $\\mathcal{O}_{F}$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Chloe Martindale University of Leiden /
IMB":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Chloe Martindale
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:f042ae60-74be-49ac-b92b-81bfa2d3b133
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20141007T100000
SUMMARY:Calcul des polynômes modulaires en genre 2
LOCATION:Salle 385
DESCRIPTION:Nous nous proposons dans un premier temps de décrire les tr
avaux de Régis Dupont (datant de 2006) quant au calcul des polynômes
modulaires en genre 2. Ces polynômes dépendent des invariants d'Igu
sa\, qui sont une généralisation de la fonction $j$ dans le genre 1\
, et permettent d'obtenir toutes les variétés abéliennes isogè
nes à une variété abélienne donnée. Dans un second temps\,
nous expliquerons comment généraliser ces polynômes à d'autres
invariants\, comment les calculer et décrirons certaines de leurs prop
riétés\, notamment le lien entre le dénominateur d'un coefficient
du polynôme modulaire et les surfaces de Humbert.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Enea Milio imb":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Enea Milio
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6a5101d0-6e92-49e6-8cc5-a884812568f8
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20141021T100000
SUMMARY:Isogeny graphs with maximal real multiplication
LOCATION:Salle 385
DESCRIPTION:An isogeny graph is a graph whose vertices are principally pol
arized abelian varieties and whose edges are isogenies between these varie
ties. In his thesis\, Kohel described the structure of isogeny graphs for
elliptic curves and showed that one may compute the endomorphism ring of a
n elliptic curve defined over a finite field by using a depth first search
algorithm in the graph. In dimension 2\, the structure of isogeny graphs
is less understood and existing algorithms for computing endomorphism ring
s are very expensive. We fully describe isogeny graphs of genus 2 jacobian
s\, with maximal real multiplication. Over finite fields\, we derive a dep
th first search algorithm for computing endomorphism rings locally at prim
e numbers\, if the real multiplication is maximal. To the best of our know
ledge\, this is the first DFS-based algorithm in genus 2. This is joint wo
rk with Emmanuel Thomé.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Sorina Ionica imb":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Sorina Ionica
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ec954622-50ad-41e4-adbc-ae78f09b4209
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20141125T100000
SUMMARY:A Pari/GP package for computing L-functions.
LOCATION:Salle 385
DESCRIPTION:Based on an idea of Pascal Molin\, we describe a GP script for
computing with L-functions of any reasonable degree. Most of the talk wil
l be computer demonstrations of examples. The audience can bring their own
favourite L-functions\, as long as they are easy to implement and most im
portantly that their conductor be not too large. This will enable me to ad
d to the examples that I will present\, and/or find bugs.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen imb":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6b5853b4-46c3-4d19-9b18-71f9bfe394ff
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20141202T100000
SUMMARY:Symbolic integration in finite characteristic
LOCATION:Salle 385
DESCRIPTION:A well-known result by Liouville shows that some elementary fu
nctions of a real or complex variable does not admit elementary antideriva
tives\, the usual example being $\\exp(-x^2)$. In 1968\, Risch gave an alg
orithm to decide if an elementary function admit an elementary antiderivat
ive. Elementary functions can be defined in term of differentials fields w
hich allow a natural definition over fields of finite characteristic. We d
iscuss the problem of elementary antiderivative in this context\, and we e
xtent it to elementary solutions to linear differential equations.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert imb":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:703b1ca0-0863-4b84-994c-8d6771db6462
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20141209T100000
SUMMARY:Une attaque polynomiale du schéma de McEliece basé sur les codes
de Goppa "sauvages".
LOCATION:Salle 385
DESCRIPTION:Le schéma de McEliece est un schéma de chiffrement basÃ
© sur les codes correcteurs d'erreurs dont la sécurité repose sur l
a difficulté à décoder un code aléatoire. Parmi les différent
es familles de codes algébriques proposées pour ce schéma\, les c
odes de Goppa classiques sont les seuls à résister à toutes les a
ttaques algébriques\, et ce\, depuis près de 35 ans. Dans cet expos
é\, je présenterai une attaque d'un genre nouveau\, dite "par filtra
tion" qui permet de retrouver la structure d'un code de Goppa "sauvage" (W
ild Goppa code) construit à partir d'une extension de corps quadratique
. Cette attaque consiste à utiliser des propriétés multiplicative
s du code pour en calculer une filtration (i.e. une famille de sous-codes
emboités) dont chaque élément est un code de Goppa classique.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Alain Couvreur INRIA & LIX\, École Poly
technique":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Alain Couvreur
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a0186811-f9f3-45e6-ad8d-ee6da2a6a3e3
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20141209T100000
SUMMARY:Une attaque polynomiale du schéma de McEliece basé sur les codes
de Goppa "sauvages".
LOCATION:Salle 385
DESCRIPTION:Le schéma de McEliece est un schéma de chiffrement basÃ
© sur les codes correcteurs d'erreurs dont la sécurité repose sur l
a difficulté à décoder un code aléatoire. Parmi les différent
es familles de codes algébriques proposées pour ce schéma\, les c
odes de Goppa classiques sont les seuls à résister à toutes les a
ttaques algébriques\, et ce\, depuis près de 35 ans. Dans cet expos
é\, je présenterai une attaque d'un genre nouveau\, dite "par filtra
tion" qui permet de retrouver la structure d'un code de Goppa "sauvage" (W
ild Goppa code) construit à partir d'une extension de corps quadratique
. Cette attaque consiste à utiliser des propriétés multiplicative
s du code pour en calculer une filtration (i.e. une famille de sous-codes
emboités) dont chaque élément est un code de Goppa classique.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Alain Couvreur INRIA & LIX\, Ãcole Po
lytechnique":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Alain Couvreur
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:0edc38ed-a63c-4059-be08-041501588296
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150127T100000
SUMMARY:Class polynomials for abelian surfaces
LOCATION:Salle 385
DESCRIPTION:The complex multiplication method is well-known for elliptic c
urves\, where it may be used to construct curves used in primality proofs
or to implement crytosystems\, in particular pairing-based ones. A similar
approach is possible for abelian surfaces\, that are Jacobians of genus 2
curves\, with considerable number theoretic complications. I describe an
algorithm using complex floating point approximations with an asymptotical
ly optimal running time\, that is\, quasi-linear in the size of the class
polynomials produced as output. Our implementation has been used to carry
out parallelised record computations and I present experimental data.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge imb":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:32dd276b-dcb8-4938-9b40-8e9ae492fe17
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150127T100000
SUMMARY:Class polynomials for abelian surfaces
LOCATION:Salle 385
DESCRIPTION:The complex multiplication method is well-known for elliptic c
urves\, where it may be used to construct curves used in primality proofs
or to implement crytosystems\, in particular pairing-based ones. A similar
approach is possible for abelian surfaces\, that are Jacobians of genus 2
curves\, with considerable number theoretic complications. I describe an
algorithm using complex floating point approximations with an asymptotical
ly optimal running time\, that is\, quasi-linear in the size of the class
polynomials produced as output. Our implementation has been used to carry
out parallelised record computations and I present experimental data.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge imb":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:87d8f2ef-89ac-48c5-a6db-db6628c93a17
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150203T103000
SUMMARY:Arithmetic Geometry and Key Exchange : Compact Diffie--Hellman wit
h Efficient Endomorphisms
LOCATION:Salle 385
DESCRIPTION:$\\newcommand{\\G}{{\\mathcal{G}}}$ Diffie--Hellman key exchan
ge is a fundamental primitive in public-key cryptography. If \\(\\G\\) is
an abelian group (written additively)\, then the Diffie--Hellman protocol
in \\(\\G\\) is composed of four computations in the form \\[ P \\longmap
sto [m]P = \\underbrace{P + \\cdots + P}_{m \\text{ times}} \\] for variou
s points \\(P\\) and integers \\(m\\)\; optimising this *scalar multiplica
tion* operation is therefore crucial.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Benjamin Smith INRIA & LIX\, École Poly
technique":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Benjamin Smith
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:61f9bb17-d244-418e-9df8-6d7b77ccd100
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150210T100000
SUMMARY:Co-volume of high-rank subgroups of the units of a number field
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Eduardo Friedman Universidad de Chile":M
AILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Eduardo Friedman
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a9db7a17-c42b-4480-86a8-a25b3ae93d00
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150303T100000
SUMMARY:A family of Artin-Schreier curves with many automorphisms
LOCATION:Salle 385
DESCRIPTION:Algebraic geometry codes are obtained from certain types of cu
rves over finite fields. Since the length of such a code is determined by
the number of rational points on the curve\, it is desirable to use curves
with as many rational points as possible. We investigate a certain class
of Artin-Schreier curves with an unusually large number of automorphisms.
Their automorphism group contains a large extraspecial subgroup. Precise k
nowledge of this subgroup makes it possible to compute the zeta functions
of these curves. As a consequence\, we obtain new examples of curves that
attain the provably maximal (or minimal) number of points over an appropri
ate field of definition.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Renate Scheidler University Calgary":MAI
LTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Renate Scheidler
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ad701e9a-3b23-41d8-a291-4be4e88688d3
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150310T100000
SUMMARY:Linearly Homomorphic Encryption from DDH
LOCATION:Salle 385
DESCRIPTION:In this talk\, we will design a linearly homomorphic encryptio
n scheme whose security relies on the hardness of the decisional Diffie-He
llman (DDH) problem. Our approach requires some special features of the un
derlying group. In particular\, its order is unknown and it contains a sub
group in which the discrete logarithm problem is tractable. Therefore\, ou
r instantiation holds in the class group of a non maximal order of an imag
inary quadratic field. Its algebraic structure makes it possible to obtain
such a linearly homomorphic scheme whose message space is the whole set o
f integers modulo a prime p and which supports an unbounded number of addi
tions modulo p from the ciphertexts. A notable difference with previous wo
rks is that\, for the first time\, the security does not depend on the har
dness of the factorization of integers. As a consequence\, under some cond
itions\, the prime p can be scaled to fit the application needs.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Guilhem Castagnos imb":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Guilhem Castagnos
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:04e350d7-71cf-4999-af49-bd573e2a8645
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150331T100000
SUMMARY:Modular symbols and p-adic L functions I
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Karim Belabas imb":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Karim Belabas
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a49228b0-f3b5-45b0-abd0-fe975086fcef
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150407T100000
SUMMARY:Modular symbols and p-adic L functions II
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Karim Belabas imb":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Karim Belabas
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:24e64c94-32d3-4bf2-b415-a8560921da9b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150414T100000
SUMMARY:Modular symbols and p-adic L functions III
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Karim Belabas imb":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Karim Belabas
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1c916f96-7ed8-48a3-aad0-e95367a21ff0
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150505T100000
SUMMARY:Arithmetic on Abelian and Kummer varieties I
LOCATION:Salle 385
DESCRIPTION:The first talk will review the arithmetic of different models
of elliptic curves and on the Kummer line. We will also review Mumford coo
rdinates for Jacobian of hyperelliptic curves and introduce theta function
s for general abelian varieties.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert imb":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:e4c257f9-bb7a-4a33-bdd3-85be39f52fd5
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150512T100000
SUMMARY:Arithmetic on Abelian and Kummer varieties II
LOCATION:Salle 385
DESCRIPTION:The second talk will focus on the arithmetic of theta function
s of level 2 and 4 and their use for Abelian and Kummer varieties cryptogr
aphy.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert imb":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:7762ea3a-6e40-40cc-b4b7-43d189b03146
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150526T100000
SUMMARY:Algorithms for finite rings
LOCATION:Salle 385
DESCRIPTION:We will discuss deterministic polynomial time algorithms desig
ned to answer a series of fundamental questions about finite rings and fin
ite modules. These include the module isomorphism problem\, computing the
minimum number of generators of a module and finding a "good" approximatio
n for the Jacobson radical of a finite ring.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Iuliana Ciocanea-Teodorescu Leiden+IMB":
MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Iuliana Ciocanea-Teodorescu
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:7a3cf035-fa13-41c1-971b-c9e94d72b3bf
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150602T100000
SUMMARY:Optimised addition sequences for eta and theta functions
LOCATION:Salle 385
DESCRIPTION:The main ingredient of complex multiplication algorithms for e
lliptic curves that compute class and modular polynomials via floating poi
nt approximations is the evaluation of Dedekind's η- and of more genera
l Ï‘-functions. While algorithms are known that are asymptotically quas
i-linear in the desired precision\, in practice it is usually faster to ev
aluate lacunary power series. It has been observed experimentally that par
ticularly short addition sequences exist for the specially structured expo
nents of η and ϑ. A leisurely stroll through classic number theory
will provide us with proofs of this fact.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge imb":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:67ffd6f4-1b44-4243-a37d-30f6c61c89a9
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150623T100000
SUMMARY:Multiplication réelle et polynômes modulaires
LOCATION:Salle 385
DESCRIPTION:Soit $K=\\mathbb{Q}(\\sqrt{2})$ ou $\\mathbb{Q}(\\sqrt{5})$. I
l existe deux invariants qu'on appelle invariants de Gundlach qui engendre
nt le corps des fonctions modulaires symétriques de Hilbert. Si $\\beta
$ est un élément totalement positif de $O_K$ de norme $p$\, les $\\b
eta$-polynômes modulaires paramétrisent les classes d'isomorphisme d
e variétés abéliennes principalement polarisées ayant multipli
cation réelle par $O_K$ et munis d'une $\\beta$-isogénie ou d'une $\
\beta^c$-isogénie. Nous décrivons un algorithme efficace pour calcul
er ces polynômes en transposant certains calculs sur l'espace de Siegel
. Nous étendrons ces méthodes à des invariants dérivés des
fonctions thêta.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Enea Milio imb":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Enea Milio
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:4af4f3a5-0709-460f-890f-dde56d969697
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150908T100000
SUMMARY:Algorithms for integer factorization and discrete logarithms compu
tation
LOCATION:Salle 385
DESCRIPTION:In this talk\, I will present some results obtained during my
Ph.D on integer factorization and discrete logarithm computation in finite
fields. First\, I will present the ECM algorithm for integer factorizatio
n and a new method to analyze the elliptic curves used in this algorithm b
y studying the Galois properties of division polynomials. Then\, I will ta
lk about the NFS algorithm for integer factorization and in particular the
polynomial selection step for which I will propose improvements of existi
ng algorithms. Finally\, I will talk about a common step of the NFS algori
thm for integer factorization and the NFS-DL and FFS algorithms for discre
te logarithm computations: the filtering step. I will explain this step th
oroughly and present an improvement for which I will study the impact usin
g data from several computations of discrete logarithms and factorizations
.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Cyril Bouvier ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Cyril Bouvier
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:4bfa00e3-7be7-4657-bdea-684dd4a5d81f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20150922T110000
SUMMARY:Analysis of the Efficiency of the point blinding countermeasure ag
ainst fault attack in Miller's algorithm.
LOCATION:Salle 385
DESCRIPTION:In this talk\, I will present fault attacks against pairing ba
sed protocols and describe some countermeasures. I will particularly show
that the point blinding countermeasure does not provide a complete protect
ion to Miller's algorithm which is the main tool for pairings.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Emmanuel Fouotsa École Normale Supérie
ure de l'Université de Bamenda":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Emmanuel Fouotsa
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:2824afd8-0ed1-468d-a95d-3fa3b9744752
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20151006T110000
SUMMARY:Constructions et evaluations de fonctions sur les varietes jacobie
nnes et leur quotients.
LOCATION:Salle 385
DESCRIPTION:Soient $K$ un corps fini\, $C$ une courbe projective absolumen
t integre sur $K$ et $\\ell$ un nombre premier impair different de la carc
teristique de $K$. Notons $W$ l'ensemble des classes d'equivalence lineair
e de diviseurs effectifs de degre 1 sur $C$. Nous nous interessons aux sec
tions globales d'un faisceau de $O_C$-modules sur la jacobienne $J_C$ de C
. Plus precisement nous allons construitre une base de l'espace des fonct
ions $f$ sur $J_C$ tels que le diviseur $div(f)+\\ell W$ est un diviseur e
ffectif sur $J_C$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Tony Ezome Université des Sciences et T
echniques de Masuku\, Franceville":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Tony Ezome
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:31158883-34f1-4b68-8440-01b90aa80d56
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20151013T110000
SUMMARY:Computing transcendental functions with error bounds
LOCATION:Salle 385
DESCRIPTION:In this talk\, I will give an overview of work I've done in th
e last year on computing various transcendental functions in interval arit
hmetic. The first notable result is a large (order of magnitude) speed imp
rovement for elementary functions. The second project concerns generalized
hypergeometric functions (including the incomplete gamma function\, Besse
l functions\, and others). This is still a work in progress\, and some sig
nificant problems remain\, particularly the task of computing useful enclo
sures when the inputs are large\, inexact complex numbers. Finally\, I hav
e a fairly complete implementation of the classical Jacobi theta functions
\, elliptic functions and modular forms. I will describe an optimization f
or theta series\, following up the results presented earlier by Andreas En
ge (2015-06-02)\, and discuss the application of computing class polynomia
ls.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Fredrik Johansson imb":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Fredrik Johansson
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:4997d9d4-dba9-47da-89da-5bdabc89853e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20151124T110000
SUMMARY:The SEA algorithm in PARI/GP
LOCATION:Salle 385
DESCRIPTION:The Schoof-Elkies-Atkin (SEA) algorithm is currently the most
efficient algorithm for counting the number of points of an elliptic curve
defined over a finite field of large characteristic. The main idea of thi
s algorithm is to use the relation between the order of the curve and the
trace of the Frobenius endomorphism and then to compute this trace modulo
small primes. Using the CRT and the Hasse-Weil bound leads to find the exa
ct value of the trace. The implementation of SEA in PARI/GP is based on Re
ynald Lercier's thesis\, published in 1997. Many improvements have been pr
oposed since. In this talk\, I will present two algorithms (respectively p
ublished by Gaudry and Morain and by Mihailescu\, Morain and Schost) to co
mpute the trace in the so-called Elkies case\, their implementations in PA
RI and comparisons I made during my master's internship in the French Netw
ork and Information Security Agency.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Julien Keuffer Morpho":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Julien Keuffer
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1a4f6a5f-191e-4d36-8ad4-858b151a337d
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20151203T100000
SUMMARY:Characterization of Sato-Tate distributions by character theory
LOCATION:Salle 385
DESCRIPTION:We describe the generalized Sato-Tate group attached to an abe
lian variety and introduce an approach to characterize it through the char
acter theory of compact Lie groups. We illustrate the method with example
s of generic curves of low genus\, with Sato-Tate group $\\mathrm{USp}(2g)
$\; special curves which yield proper subgroups\, and a family of Katz giv
ing rise to Galois representations in $\\mathrm{SO}(2g+1)$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="David Kohel Université d'Aix-Marseille"
:MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:David Kohel
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ef15c76c-58e8-4f9f-88f4-35b6f0118502
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20151215T110000
SUMMARY:Les aspect combinatoires des fonctions L d'Artin.
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert imb":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:014b37e5-4d3f-4edf-b080-6804dfd7a670
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20160126T110000
SUMMARY:Présentation de WIMS (WWW Interactive Multipurpose Server)
LOCATION:Salle 1
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bernadette Perrin-Riou Université Paris
-Sud":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bernadette Perrin-Riou
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:261182fd-61fd-412d-b639-e143f86b08e0
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20160209T110000
SUMMARY:L-functions of Genus Two Abelian Coverings of Elliptic Curves over
Finite Fields
LOCATION:Salle 385
DESCRIPTION:Initially motivated by the relations between Anabelian Geometr
y and Artin's L-functions of the associated Galois-representations\, here
we study the list of zeta-functions of genus two abelian coverings of elli
ptic curves over finite fields. Our goal is to provide a complete descript
ion of such a list.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Павел Соломатин imb":MAILT
O:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Павел Соломатин
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a6b8b9e9-74b8-40f6-ac0c-b6abff98b68b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20160301T110000
SUMMARY:Nonlinear polynomial selection for the number field sieve: improvi
ng Montgomery's method
LOCATION:Salle 385
DESCRIPTION:The number field sieve is the most efficient known algorithm f
or factoring large integers that are free of small prime factors. The goal
of the polynomial selection\, the first stage of this algorithm\, is to c
ompute a pair of integer polynomials. Montgomery proposed a method for gen
erating two nonlinear polynomials which relies on the construction of smal
l modular geometric progressions. In this talk\, I will present theoretica
l and practical improvements to Montgomery's method that allow us to gener
ate pairs of a quadratic and a cubic polynomials and pairs of two cubic po
lynomials for larger integer that was previously possible. Joint work with
Nicholas Coxon.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Cyril Bouvier imb":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Cyril Bouvier
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:02c0ec26-2fed-4752-be55-5ce6bbb2cc66
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20160308T110000
SUMMARY:Régulateurs de corps de nombres et de variétés abéliennes et p
ropriété de Northcott.
LOCATION:Salle 385
DESCRIPTION:Soit $A$ une variété abélienne définie sur un corp
s de nombres $K$. On peut définir un régulateur associé au groupe
de Mordell-Weil des points rationnels $A(K)$\, lequel joue un rôle imp
ortant dans la forme forte de la conjecture de Birch et Swinnerton-Dyer. S
i l'on suppose vraie la conjecture de Lang et Silverman\, on montre alors
que ce régulateur vérifie la propriété de finitude suivante :
il n'y a qu'un nombre fini de variétés abéliennes simples de dime
nsion fixée $g$\, définie sur $K$\, de rang non nul et de régulat
eur borné. On montre de plus (dans le courant de la preuve) une inég
alité inconditionnelle entre la hauteur de Faltings de $A$\, les premie
rs de mauvaise réduction de $A$ et le rang de Mordell-Weil de $A$. L'ex
posé commencera par une introduction présentant un résultat simil
aire et inconditionnel pour les régulateurs de familles de corps de nom
bres.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Fabien Pazuki IMB et Université de Cope
nhague":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Fabien Pazuki
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:23b20fbd-d2ba-4473-a5a0-07a29550a9c5
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20160315T110000
SUMMARY:Survey on computing isogeny between elliptic curves.
LOCATION:Salle 385
DESCRIPTION:We present methods to compute isogenies between elliptic curve
s\, and we apply them to the computation of the isogenies matrix of an ell
iptic curve defined over the rational and to the Schoof Elkies Atkin algor
ithm for counting point on elliptic curves defined over a finite field.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert imb":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:8094f51c-05c2-4a3c-b82e-8138b7dce7e1
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20160322T110000
SUMMARY:Formules de Thomae généralisées aux cas des extensions galoisie
nnes résolubles de $\\mathbb{P}^1$.
LOCATION:Salle 385
DESCRIPTION:D'un point de vue classique\, les formules de Thomae relient d
es rapports de puissances de theta constantes avec les coordonnées affi
nes des points de ramification d'une courbe hyperelliptique. A partir des
années 80\, plusieurs auteurs\, ayant des préoccupations centrés
sur la physique\, ont montré des généralisations de ces formules
au cas des courbes superelliptiques. Plus récemment\, Shau Zemel et Her
shel Farkas ont écrit un livre en utilisant des arguments essentielleme
nt algébriques. D'un point de vue arithmétique\, ces courbes corresp
ondent à des extensions galoisiennes cycliques d'un corps de fonctions
$k(x)$. Nous montrerons comment généraliser ces formules au cas des
extensions résolubles de $k(x)$ et quelles obstructions peuvent surveni
r.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Alexandre Le Meur Université de Rennes"
:MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Alexandre Le Meur
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:df9671de-05bf-4dbc-8529-c389a237d3f9
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20160405T110000
SUMMARY:A database of rational elliptic curves with given bad reduction
LOCATION:Salle 385
DESCRIPTION:In this talk we present a database of rational elliptic curves
with good reduction outside certain finite sets of primes\, including the
set {2\, 3\, 5\, 7\, 11}\, and all sets whose product is at most 1000.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Benjamin Matschke IMB":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Benjamin Matschke
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:8898d8ee-d773-48c4-8548-ba59e0fce0f4
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20160510T110000
SUMMARY:Calcul de représentations galoisiennes modulaires / Computing mod
ular Galois representations
LOCATION:Salle 385
DESCRIPTION:Nous verrons comment la représentation galoisienne modulo l
associée à une forme modulaire classique peut être calculée eff
icacement\, en l'isolant dans la torsion de la jacobienne d'une courbe mod
ulaire. Ceci permet notamment de calculer les coefficients a(p) de la form
e en temps polynomial en log p\, ce qui en fait la méthode la plus effi
cace connue à ce jour.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Nicolas Mascot University of Warwick":MA
ILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Nicolas Mascot
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:4fa0bd45-1e30-4322-aa4f-377eb9d92a43
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20160517T110000
SUMMARY:Certification de représentations galoisiennes modulaires / Certif
ying modular Galois representations
LOCATION:Salle 385
DESCRIPTION:Nous verrons comment les calculs de représentations galoisi
ennes présentés dans l'exposé précédent peuvent être cer
tifiés\, en s'appuyant sur la conjecture de modularité de Serre et d
es calculs explicites de cohomologie des groupes.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Nicolas Mascot University of Warwick":MA
ILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Nicolas Mascot
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:dcd5dfa0-d7d2-4830-a6c8-68ba72d2e8ef
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20160607T100000
SUMMARY:Tower decomposition of Hilbert class fields
LOCATION:Salle 385
DESCRIPTION:The genus g function Theta : $\\mathbb{C}^g x \\mathfrak{H}_g
-> \\mathbb{C}$ has numerous applications in mathematics\, from number the
ory to non-linear differential equations\; in particular\, its connection
with the Abel-Jacobi map on complex elliptic and hyperelliptic curves has
important applications. A connection between some values of this function
(the theta-constants) and the arithmetico-geometric mean of Gauss (and its
generalization in genus $g$\, the Borchardt mean) yields an algorithm to
compute any $P$ digits of the theta-constants in roughly $\\mathrm{log} P$
multiplication of $P$-bit numbers\, which is quasi-optimal. We provide a
generalization of this connection using general tau-duplication formulas\;
with some care\, this allows us to devise an algorithm to compute $P$ dig
its of Theta in the same quasi-linear time in $P$. We also report on an im
plementation in genus 1 and 2\, which beats the naive algorithm for precis
ions as low as a few thousand digits. This is joint work with Emmanuel Tho
mé.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jared Asuncion IMB":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jared Asuncion
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:e3963b86-0bab-409d-85c9-508774602338
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20161011T140000
SUMMARY:Une implantation en genre 2 de "Computing functions on Jacobians a
nd their quotients" de Jean-Marc Couveignes et Tony Ezome
LOCATION:Salle 385
DESCRIPTION:Cet article explique comment définir et évaluer des fonc
tions sur des Jacobiennes de courbes de genre $g$ et sur des quotients de
telles Jacobiennes par des sous-groupes isotropes maximaux de la $\\ell$-t
orsion\, pour $\\ell>2$ premier. Pour le cas spécifique du genre 2\, il
est bien connu qu'Ã partir d'une courbe hyperelliptique $C$ et d'un so
us-groupe isotrope maximal $V$\, le quotient $\\mathrm{Jac}(C)/V$ est la J
acobienne d'une courbe hyperelliptique $C'$\, $(\\ell\,\\ell)$-isogène
à $C$. L'application de $C$ vers $\\mathrm{Jac}(D)$ peut être déc
rite avec des fractions rationnelles de degré en $O(\\ell)$. L'article
donne une méthode pour calculer $C'$ et ces fractions. Pour notre expos
é\, nous nous proposons d'exposer le contenu de ce papier et de parler
de l'implantation que nous avons faite en genre 2.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Enea Milio Inria Nancy Grand Est":MAILTO
:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Enea Milio
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:e5661fab-cd45-42e0-8a25-7f28cb2bdaf4
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20161018T100000
SUMMARY:Computing ray class fields of imaginary quadratic fields
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Gregor Seiler ETH Zurich":MAILTO:null@ma
th.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Gregor Seiler
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:570211b5-50d6-4bdc-827d-69e42488d35e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20161108T100000
SUMMARY:Algorithmes BMSS et Lercier Sirvent pour SEA dans PARI
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Aurélien Focqué ":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Aurélien Focqué
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1dddd8a1-150e-48d0-8bf7-a3b88ca4cb4b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20161122T100000
SUMMARY:A brief history of pairings
LOCATION:Salle 385
DESCRIPTION:Pairings are a relatively new cryptographic tool which have be
en the object of many arithmetic works. In the last few years some of the
pairings have become obsolete because of the progress on the underlying pr
oblem of discrete logarithm in finite fields. We propose ourselves to make
a list of pairings constructions\, to explain their advantages but also t
heir weaknesses. The sporadic curves are vulnerable to the Logjam attack a
nd have never been a popular choice. The small characteristic curves allow
a very good arithmetic but are the target of a quasi-polynomial algorithm
. The pairings where the characteristic has a low Hamming weight\, which e
liminate the cost of modular reductions\, have been the object of special
attacks. When the embedding degree is composite the one can use the tower
field arithmetic but there are also tower field attacks.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Razvan Barbulescu ":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Razvan Barbulescu
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:20c6c68e-d389-49c7-9478-7e0ab453059c
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20170117T100000
SUMMARY:Tuple lattice sieving
LOCATION:Salle 385
DESCRIPTION:Lattice sieving is asymptotically the fastest approach for sol
ving the shortest vector problem (SVP) on Euclidean lattices. All known si
eving algorithms for solving SVP require space which (heuristically) grows
as $2^{0.2075n+o(n)}$\, where n is the lattice dimension. In high dimensi
ons\, the memory requirement becomes a limiting factor for running these a
lgorithms\, making them uncompetitive with enumeration algorithms\, despit
e their superior asymptotic time complexity. We generalize sieving algorit
hms to solve SVP with less memory. We consider reductions of tuples of vec
tors rather than pairs of vectors as existing sieve algorithms do. For tri
ples\, we estimate that the space requirement scales as $2^{0.1887n+o(n)}$
. The naive algorithm for this triple sieve runs in time $2^{0.5661n+o(n)}
$. With appropriate filtering of pairs\, we reduce the time complexity to
$2^{0.4812n+o(n)}$ while keeping the same space complexity. We further ana
lyze the effects of using larger tuples for reduction\, and conjecture how
this provides a continuous tradeoff between the memory-intensive sieving
and the asymptotically slower enumeration. Joint work with Shi Bai\, Thijs
Laarhoven
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Stehlé ENS Lyon":MAILTO:null@mat
h.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Stehlé
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c88bf37d-4b33-482d-a1c3-e3eb81fab0f3
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20170314T100000
SUMMARY:Nearly sparse linear algebra
LOCATION:Salle 385
DESCRIPTION:Linear algebra is a widely used tool both in mathematics and c
omputer science\, and cryptography is no exception to this rule. Yet\, it
introduces some particularities\, such as dealing with linear systems that
are often sparse\, or\, in other words\, linear systems inside which a lo
t of coefficients are equal to zero. We propose to enlarge this notion to
nearly sparse matrices\, characterized by the concatenation of a sparse ma
trix and some dense columns\, and to design an algorithm to solve this kin
d of problems. Motivated by discrete logarithms computations on medium and
high characteristic finite fields\, the Nearly Sparse Linear Algebra brid
ges the gap between classical dense linear algebra problems and sparse lin
ear algebra ones\, for which specific methods have already been establishe
d. Our algorithm particularly applies on one of the three phases of NFS (N
umber Field Sieve) which precisely consists in finding a non trivial eleme
nt of the kernel of a nearly sparse matrix.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Cécile Pierrot Centrum Wiskunde & Infor
matica\, Amsterdam":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Cécile Pierrot
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:adbbf7be-d16b-4d1b-b9e5-f5b4283800e7
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20170523T100000
SUMMARY:Post-quantum cryptography from supersingular isogeny problems?
LOCATION:Salle 385
DESCRIPTION:We review existing cryptographic schemes based on the hardness
of computing isogenies between supersingular isogenies\, and present some
attacks against them. In particular\, we present new techniques to accele
rate the resolution of isogeny problems when the action of the isogeny on
a large torsion subgroup is known\, and we discuss the impact of these tec
hniques on the supersingular key exchange protocol of Jao-de Feo.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Christophe Petit Oxford":MAILTO:null@mat
h.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Christophe Petit
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:2d1b61ce-dd03-434a-b5e8-3916374d1bfe
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20170530T100000
SUMMARY:Isogeny graphs of ordinary abelian varieties
LOCATION:Salle 385
DESCRIPTION:Fix a prime number $\\ell$. Graphs of isogenies of degree a po
wer of $\\ell$ are well-understood for elliptic curves\, but not for highe
r-dimensional abelian varieties. We study the case of absolutely simple or
dinary abelian varieties over a finite field. We analyse graphs of so-call
ed $\\mathfrak l$-isogenies\, resolving that\, in arbitrary dimension\, th
eir structure is similar\, but not identical\, to the ``volcanoes'' occurr
ing as graphs of isogenies of elliptic curves. Specializing to the case of
principally polarizable abelian surfaces\, we then exploit this structure
to describe graphs of a particular class of isogenies known as $(\\ell\,
\\ell)$-isogenies. These results lead to new\, provable algorithms to navi
gate in isogeny graphs\, with consequences for the CM-method in genus 2\,
for computing explicit isogenies\, and for the random self-reducibility of
the discrete logarithm problem in genus 2 cryptography.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Benjamin Wesolowski EPFL":MAILTO:null@ma
th.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Benjamin Wesolowski
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1749771f-8f81-4aec-8061-f75aba00275d
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20170606T100000
SUMMARY:Encryption Switching Protocols Revisited: Switching modulo p
LOCATION:Salle 385
DESCRIPTION:Last year\, Couteau\, Peters and Pointcheval introduced a new
primitive called encryption switching protocols\, allowing to switch ciphe
rtexts between two encryption schemes. If such an ESP is built with two sc
hemes that are respectively additively and multiplicatively homomorphic\,
it naturally gives rise to a secure 2-party computation protocol. It is t
hus perfectly suited for evaluating functions\, such as multivariate polyn
omials\, given as arithmetic circuits. Couteau et al. built an ESP to swit
ch between Elgamal and Paillier encryptions which do n ot naturally fit we
ll together. Consequently\, they had to design a clever variant of Elgamal
over Z/nZ with a costly shared decryption. In this talk\, we first presen
t a conceptually simple generic construction for encryption switching prot
ocols. We then give an efficient instantiation of our generic approach tha
t uses two well-suited protocols\, namely a variant of Elgamal in Z/pZ and
the Castagnos-Laguillaumie encryption defined over class groups of quadra
t ic fields which is additively homomorphic over Z/pZ. Among other advanta
ges\, this allows to perform all computations modulo a prime p instead of
an RSA modulus. Overall\, our solution leads to significant reductions in
the number of rounds as well as the number of bits exchanged by the parti
es during the interactive protocols. We also show how to extend its secur
ity to the malici ous setting.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Guilhem Castagnos imb":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Guilhem Castagnos
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c568448d-f7d0-4fb0-b485-6bed94d15f19
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20170613T100000
SUMMARY:The Anti-Field-Descent Method
LOCATION:Salle 385
DESCRIPTION:A circulant Hadamard matrix of order $v$ is a matrix of the f
orm \\[H=\\begin{pmatrix} a_1 & a_2 & \\cdots & a_v \\\\ a_v & a_1 & \\cdo
ts & a_{v-1} \\\\ \\cdots & \\cdots & \\cdots &\\cdots \\\\ a_2 & a_3 & \\
cdots & a_1 \\\\ \\end{pmatrix}\\] with $a_i=\\pm 1$ such that any two row
s of $H$ are orthogonal with respect to the standard inner product. It is
conjectured that there is no circulant Hadamard matrix of order larger tha
n $4$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bernhard Schmidt Nanyang Technological U
niversity\, Singapore":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bernhard Schmidt
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:3e3df6db-ac35-4489-afd1-202cfa1af50a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20171017T100000
SUMMARY:Numerics of classical elliptic functions\, elliptic integrals and
modular forms
LOCATION:Salle 385
DESCRIPTION:We review methods for validated arbitrary-precision numerical
computation of elliptic functions and their inverses (the complete and inc
omplete elliptic integrals)\, as well as the closely related Jacobi theta
functions and $\\mathrm{SL}_2(\\mathbb{Z})$ modular forms. A general strat
egy consists of two stages: first\, using functional equations to reduce t
he function arguments to a smaller domain\; second\, evaluation of a suita
ble truncated series expansion. For elliptic functions and modular forms\,
one exploits periodicity and modular transformations for argument reducti
on\, after which the rapidly convergent series expansions of Jacobi theta
functions can be employed. For elliptic integrals\, a comprehensive strate
gy pioneered by B. Carlson consists of using symmetric forms to unify and
simplify both the argument reduction formulas and the series expansions (w
hich involve multivariate hypergeometric functions). Among other aspects\,
we discuss error bounds as well as strategies for argument reduction and
series evaluation that reduce the computational complexity. The functions
have been implemented in arbitrary-precision complex interval arithmetic a
s part of the Arb library.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Fredrik Johansson imb":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Fredrik Johansson
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:5cee100b-f27e-4f60-bc4e-18012c1788d1
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20171024T100000
SUMMARY:Context-free languages in Algebraic Geometry and Number Theory.
LOCATION:Salle 385
DESCRIPTION:Kassel and Reutenauer computed the zeta function of the Hilber
t scheme of n points on a two-dimensional torus and showed it satisfies se
veral number-theoretical properties via modular forms. Classifying the sin
gularities of this rational function into zeros and poles\, we define a wo
rd which contains a lot of number-theoretical information about n (the abo
ve-mentioned number of points). This nontrivial connection between natural
numbers and words can be used to define many classical subsets of natural
numbers in terms of rational and context-free languages (e.g. the set of
semi-perimeters of Pythagorean triangles\, the set of numbers such that an
y partition into consecutive parts has an odd number of parts). Also\, som
e arithmetical functions can be described in way (e.g. the Erdös-Nicola
s function\, the number of middle divisors). Finally\, this approach provi
des a new technique to prove number-theoretical results just using relatio
nships among context-free languages.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="José Manuel Rodriguez Caballero Labri":
MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:José Manuel Rodriguez Caballero
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a151d2ff-e241-4810-aac9-cbfc65a96167
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20171114T100000
SUMMARY:Accélération du protocole d'échange de clés de Couveignes-Rost
ovtsev-Stolbunov
LOCATION:Salle 385
DESCRIPTION:Ce protocole d'échange de clés est fondé sur la thÃ
©orie de la multiplication complexe: un ordre dans un corps quadratique i
maginaire agit sur un ensemble de courbes elliptiques ordinaires isogèn
es définies sur un corps fini. Pour instancier le protocole\, on est am
ené à calculer des isogénies de différents degrés entre ces
courbes à l'aide des algorithmes développés pour le comptage de
points. Ce cryptosystème peut être accéléré par un bon choi
x de courbe elliptique initiale\, notamment par la présence de points d
e torsion rationnels\, et l'on présente une méthode de recherche de
telles courbes.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean Kieffer ENS Paris":MAILTO:null@math
.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean Kieffer
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:2d83715b-9a0f-4799-ac1e-2bb3976eb296
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20171120T140000
SUMMARY:Computational approach to compact Riemann surfaces
LOCATION:Salle 385
DESCRIPTION:A purely numerical approach to compact Riemann surfaces starti
ng from plane algebraic curves is presented. The critical points of the al
gebraic curve are computed via a two-dimensional Newton iteration. The sta
rting values for this iteration are obtained from the resultants with resp
ect to both coordinates of the algebraic curve and a suitable pairing of t
heir zeros. A set of generators of the fundamental group for the complemen
t of these critical points in the complex plane is constructed from circle
s around these points and connecting lines obtained from a minimal spannin
g tree. The monodromies are computed by solving the de ning equation of th
e algebraic curve on collocation points along these contours and by analyt
ically continuing the roots. The collocation points are chosen to correspo
nd to Chebychev collocation points for an ensuing Clenshaw–Curtis i
ntegration of the holomorphic differentials which gives the periods of the
Riemann surface with spectral accuracy. At the singularities of the algeb
raic curve\, Puiseux expansions computed by contour integration on the cir
cles around the singularities are used to identify the holomorphic differe
ntials. The Abel map is also computed with the Clenshaw–Curtis algo
rithm and contour integrals. As an application of the code\, solutions to
the Kadomtsev–Petviashvili equation are computed on non-hyperellipt
ic Riemann surfaces.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Christian Klein ":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Christian Klein
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:731abdf4-a5af-403b-9289-90b7d670ebb0
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20171128T100000
SUMMARY:Coloring the Voronoi tessellation of lattices
LOCATION:Salle 385
DESCRIPTION:We define the chromatic number of a lattice: It is the least n
umber of colors one needs to color the interiors of the cells of the Voron
oi tesselation of a lattice so that no two cells sharing a facet are of th
e same color. We compute the chromatic number of the irreducible root latt
ices and for this we apply a generalization of the Hoffman bound.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Frank Vallentin ":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Frank Vallentin
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:aa060b76-5877-4144-adf5-f607fd459d7a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20180109T100000
SUMMARY:Numerical integration in complex interval arithmetic
LOCATION:Salle 385
DESCRIPTION:We present a new implementation of validated arbitrary-precisi
on numerical evaluation of definite integrals $\\int_a^b f(x) dx$\, availa
ble in the Arb library. The code uses a version of the Petras algorithm\,
which combines adaptive subdivision with Gauss-Legendre (GL) quadrature\,
evaluating the integrand on complex intervals surrounding the path of inte
gration to obtain rigorous error bounds. The first part of the talk discus
ses the general algorithm and its performance for interesting families of
integrals. The second part\, which is based on joint work with Marc Mezzar
obba\, discusses the fast computation of GL quadrature nodes with rigorous
error bounds. It is well known that GL quadrature achieves a nearly optim
al rate of convergence for analytic integrands with singularities well iso
lated from the path of integration\, but due to the cost of generating GL
quadrature nodes\, the more slowly converging Clenshaw-Curtis and double e
xponential quadrature rules have often been favored when an accuracy of se
veral hundreds or thousands of digits is required. We consider the asympto
tic and practical aspects of this problem. An order-of-magnitude speedup i
s obtained over previous code for computing GL nodes with simultaneous hig
h degree and precision\, which makes GL quadrature viable even at very hig
h precision.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Fredrik Johansson imb":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Fredrik Johansson
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:47d4e9f6-02f5-4270-8c65-ea8f4e833e32
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20180122T100000
SUMMARY:On the Density of Sets Avoiding Parallelohedron Distance 1
LOCATION:Salle 2
DESCRIPTION:Let $\\Vert \\cdot \\Vert$ be a norm on $\\mathbb{R}^n$. We co
nsider the so-called unit distance graph $G$ associated with $\\Vert \\cdo
t \\Vert$: the vertices of $G$ are the points of $\\mathbb{R}^n$\, and the
edges connect the pairs $\\{x\,y\\}$ satisfying $\\Vert x-y\\Vert=1$. We
define $m_1\\left(\\mathbb{R}^n\,\\Vert \\cdot \\Vert\\right)$ as the supr
emum of the densities achieved by independent sets of $G$. The number $m_1
$ was introduced by Larman and Rogers (1972) as a tool to study the measur
able chromatic number $\\chi_m(\\mathbb{R}^n)$ of $\\mathbb{R}^n$ for the
Euclidean norm.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Philippe Moustrou IMB":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Philippe Moustrou
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:3c21e11d-4469-47f3-a631-36bab169cbd3
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20180130T100000
SUMMARY:ECPP in PARI/GP
LOCATION:Salle 385
DESCRIPTION:The elliptic curve primality proving (ECPP) algorithm not only
proves (or disproves) the primality of an integer $N$ but also provides\,
if $N$ is prime\, a primality certificate which one can verify quickly. I
n this talk\, we recall the steps of ECPP and discuss its implementation i
n PARI/GP.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jared Asuncion IMB":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jared Asuncion
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:b66e465e-c383-467e-85c1-dbd65b2cbab6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20180306T100000
SUMMARY:Class number calculation for special number fields
LOCATION:Salle 385
DESCRIPTION:I will talk about TC (an interpreter of multiprecision C langu
age which I developed)\, Weber's problem\, Coates' conjecture and an algor
ithm of calculating p-class group of abelian number fields. I also present
my project trying to implement an algorithm mentioned above to PARI/GP du
ring my stay at IMB.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Takashi Fukuda Nihon University":MAILTO:
null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Takashi Fukuda
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:9d04b1bb-0cd5-45a8-8655-3017dbbe4cb6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20180320T100000
SUMMARY:Sur les équations différentielles $p$-adiques à variables sépa
rables
LOCATION:Salle 385
DESCRIPTION:Les trois dernières décennies ont vu le développement
de méthodes et algorithmes $p$-adiques\, notamment :
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Tristan Vaccon Université de Limoges":M
AILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Tristan Vaccon
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:cc9d9a43-3073-4e58-b077-33b3ea12bf71
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20180403T100000
SUMMARY:Cohen-Martinet heuristics revisited
LOCATION:Salle 385
DESCRIPTION:In the early 1990s Henri Cohen and Jacques Martinet offered a
probabilistic model that explains the behaviour of ideal class groups of n
umber fields in natural families\, generalising earlier work by Cohen and
Lenstra. There is a lot of numerical evidence for the correctness of the m
odel\, but very few theorems. In joint work with Hendrik Lenstra we revisi
t the Cohen-Martinet heuristics and\, among other things\, disprove them i
n two different ways\, but also lend additional support for the expectatio
n that they are "basically true". In this talk I will explain one of these
disproofs\, and will propose possible corrections.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Alex Bartel Glasgow University":MAILTO:n
ull@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Alex Bartel
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c9ea8bda-440d-4556-a30b-d240a3746b3e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20180424T100000
SUMMARY:Huang's proposal for trilinear maps
LOCATION:Salle 385
DESCRIPTION:In a recent [paper](https://arxiv.org/abs/1803.10325)\, Huang
proposed a trilinear map involving abelian varieties over finite fields. I
n this talk we present his approach.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert imb":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:3f1da4b6-8ee8-4714-808c-add1aefb6598
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20180522T100000
SUMMARY:Étude et implémentation de l'algorithme de Schoof–Elkies–Atk
in
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean Kieffer ENS Paris":MAILTO:null@math
.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean Kieffer
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ef19fe5a-6a5c-4382-823a-6d3fadcba431
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20180612T100000
SUMMARY:Variations autour d'un théorème de Christol
LOCATION:Salle 385
DESCRIPTION:Un célèbre théorème de Christol affirme qu'une sÃ
©rie à coefficients dans $\\mathbb{Z}/p\\mathbb{Z}$ est algébrique
sur $\\mathbb{Z}/p\\mathbb{Z}(x)$ si et seulement si la suite de ses coeff
icients est $p$-automatique.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Xavier Caruso Université de Rennes":MAI
LTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Xavier Caruso
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:eca0cd2c-f028-478f-a623-a27d9486e3d2
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20180705T100000
SUMMARY:Fast multiquadratic S-unit computation and application to the calc
ulation of class groups
LOCATION:Salle 385
DESCRIPTION:Let $L=Q(√d_1\, ... \,√d_n)$ be a real multiquadrati
c field and S be a set of prime ideals of L that does not contain any divi
sors of 2. In this paper\, we present a heuristic algorithm for the comput
ation of the S-class group and the S-unit group that runs in time $Poly(lo
g(∆)\,Size(S)) e^{Õ(√ln d)}$ where $d=max_{i≤n} d_i$
and ∆ is the discriminant of L. We use this method to compute the id
eal class group of the maximal order $O_L$ of L in time $Poly(log(∆)
) e^{Õ(√log d)}$. When $log(d)≤log(log(∆))^c$ for som
e constant $c < 2$\, these methods run in polynomial time. We implemented
our algorithm using Sage 7.5.1.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean-François Biasse University of Sout
h Florida":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean-François Biasse
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:f3f39d99-a5bc-4fb7-adc0-6e57b35e0e0a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20180918T103000
SUMMARY:Mini groupe de travail: calcul des caractères de Hecke
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Aurel Page et Pascal Molin ":MAILTO:null
@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Aurel Page et Pascal Molin
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:5419f954-68d9-4c15-9850-6f4c37c2d080
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20181106T100000
SUMMARY:Calcul d'isogénies en genre 2
LOCATION:Salle 385
DESCRIPTION:Étant donné une courbe algébrique $C$ de genre $2$ d
éfinie sur un corps fini $K$ de caractéristique impaire et un sous-g
roupe isotrope maximal $\\mathcal{V}$ (pour le couplage de commutateur) de
l'ensemble des points de $l$-torsion où $l$ est un entier (premier) im
pair\, nous savons que le quotient de la jacobienne $J_K(C)$ de $C$ par $\
\mathcal{V}$ est une variété abélienne de dimension 2 et donc la
jacobienne d'une courbe $D$ de genre $2$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Elie Eid Université de Rennes":MAILTO:n
ull@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Elie Eid
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:3f202d93-bfb3-4ed0-a561-df9b928f2650
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20181127T100000
SUMMARY:Practical fully secure unrestricted inner product functional encry
ption modulo a prime p. (Chiffrement fonctionel sans restrictions pour le
calcul de produits scalaires modulo un nombre premier.)
LOCATION:Salle 385
DESCRIPTION:Functional encryption (FE) is an advanced cryptographic primit
ive which allows\, for a single encrypted message\, to finely control how
much information on the encrypted data each receiver can recover. To this
end many functional secret keys are derived from a master secret key. Each
functional secret key allows\, for a ciphertext encrypted under the assoc
iated public key\, to recover a specific function of the underlying plaint
ext.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Ida Tucker ":MAILTO:null@math.u-bordeaux
.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Ida Tucker
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6906794e-4be1-4d06-abb1-db3877d1a2af
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20181204T110000
SUMMARY:Torsion analytique et torsion de Reidemeister en théorie des nomb
res
LOCATION:Salle 385
DESCRIPTION:Je ferai un exposé de style groupe de travail sur le rôl
e de la torsion dans l'homologie des groupes arithmétiques en théori
e des nombres \; je présenterai une méthode permettant d'obtenir de
l'information dessus : la formule de Cheeger--Mueller\, et ses utilisation
s notamment par Bergeron--Venkatesh et Calegari--Venkatesh. Je parlerai au
ssi d'un travail que je viens de commencer avec Michael Lipnowski et Jean
Raimbault\, dont les aspects algorithmiques ont des points communs avec le
s méthodes de calcul de valeurs de fonctions L.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Aurel Page ":MAILTO:null@math.u-bordeaux
.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Aurel Page
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:840b6b68-a058-45ba-b607-43331435d1ab
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20181211T100000
SUMMARY:Torsion analytique et torsion de Reidemeister en théorie des nomb
res 2
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Aurel Page ":MAILTO:null@math.u-bordeaux
.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Aurel Page
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1060b0d2-8506-431f-a1c4-5380b7abd731
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20181218T100000
SUMMARY:Sur le calcul de automorphismes d'un extension Galoisienne niltpot
ente de corps de nombres.
LOCATION:Salle 385
DESCRIPTION:Je présente un nouvel algorithme en temps polynomial sous G
RH pour le calcul des automorphismes d'une extension Galoisienne de corps
de nombres sous la condition que le groupe de Galois soit nilpoltent. Cet
algorithme est basé sur la présentation des groupes nilpoltents et
le relèvement des automorphismes de Frobenius et évite la couteuse r
econnaissance de nombres algébriques par réduction de réseau tout
en évitant le cout exponentiel des méthodes combinatoires utilisÃ
©es dans ma thèse.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bill Allombert imb":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bill Allombert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:0fcfaa36-ab67-4d5c-95e1-c234a2bf9ef2
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20190219T100000
SUMMARY:Improving the AGM point counting algorithm
LOCATION:Salle 385
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="David Lubicz ":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:David Lubicz
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1357ac5d-ebc5-46cc-95ee-2f2512945c6f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20190409T113000
SUMMARY:Vers les codes de Gabidulin géométriques
LOCATION:Salle 385
DESCRIPTION:Dans cet exposé\, je commencerai par rappeler la définit
ion et les principales propriétés de codes de Reed-Solomon. Je prÃ
©senterai ensuite deux extensions classiques de ces codes\, Ã savoir\,
d'une part\, les codes géométriques et\, d'autre part\, les codes d
e Gabidulin. Ces deux extensions appaissent toutefois comme orthogonales :
du point de vue pratique\, elles gomment des limitations différentes d
e codes de Reed-Solomon tandis que\, du point de vue technique\, elles son
basées sur des constructions mathématiques également très dif
férentes. Dans une deuxième partie de l'exposé\, je présentera
i quelques idées et quelques résultats en vue d'une généralisa
tion commune des codes géométriques et des codes de Reed-Solomon.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Xavier Caruso imb":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Xavier Caruso
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:7af93ed9-8ec0-4c37-b1bf-21132aa3c0b8
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20190528T100000
SUMMARY:A conjectural improvement for inequalities involving the regulator
of number fields
LOCATION:Salle 385
DESCRIPTION:Given the family of number fields with fixed signature\, there
exists only a finite number of such fields having regulator less than a p
rescribed bound: this is due to a classical inequality by Remak\, generali
zed years later by Friedman\, which bounds the discriminant of a number fi
eld by means of some terms which depend also on the regulator.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Francesco Battistoni University of Milan
":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Francesco Battistoni
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:b59129bc-bd6f-4f2c-b985-724e6db255f0
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20190604T100000
SUMMARY:Équirépartition de sommes de coefficients de formes modulaires e
n progression arithmétique.
LOCATION:Salle 385
DESCRIPTION:Après avoir rappelé des résultats classiques d'équ
irépartition de sommes d'exponentielles\, j'expliquerai en quoi ce genr
e de propriétés permet de mieux comprendre les sommes de coefficient
s de Fourier de formes modulaires en progression arithmétique. Je donne
rai un aperçu de ce qui a été démontré auparavant dans cett
e thématique pour mieux introduire certaines questions restant ouvertes
auxquelles je m'intéresse\, notamment le cas des formes modulaires de
poids demi-entier.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Corentin Darreye imb":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Corentin Darreye
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:dde90db9-3ea2-4306-af1a-607d7e5ef1de
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20190910T093000
SUMMARY:The inverse Galois problem for p-adic fields
LOCATION:Salle 2
DESCRIPTION:We describe a method for counting the number of extensions of
$\\mathbb{Q}_p$ with a given Galois group $G$\, founded upon the descripti
on of the absolute Galois group of $\\mathbb{Q}_p$ due to Jannsen and Wing
berg. Because this description is only known for odd $p$\, our results do
not apply to $\\mathbb{Q}_2$. We report on the results of counting such ex
tensions for $G$ of order up to $2000$ (except those divisible by 512)\, f
or $p = 3$\, 5\, 7\, 11\, 13. In particular\, we highlight a relatively sh
ort list of minimal $G$ that do not arise as Galois groups. Motivated by t
his list\, we prove two theorems about the inverse Galois problem for $\\m
athbb{Q}_p$: one giving a necessary condition for G to be realizable over
$\\mathbb{Q}_p$ and the other giving a sufficient condition.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="David Roe MIT":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:David Roe
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1f58e7e2-8e79-46d8-ab93-1a6d908aa6a2
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20190917T100000
SUMMARY:Fungrim : The Mathematical Functions Grimoire
LOCATION:Salle 2
DESCRIPTION:[Fungrim](http://fungrim.org) is a new\, open source database
of formulas and tables for mathematical functions. All formulas are repres
ented in symbolic\, computer-readable form and include explicit conditions
for the variables.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Fredrik Johansson imb":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Fredrik Johansson
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:40837fc7-eb91-4237-8869-f01081450a4a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20190924T100000
SUMMARY:Computing isogenies from modular equations in genus 2
LOCATION:Salle 2
DESCRIPTION:Given two elliptic curves such an isogeny of degree l exists b
etween them\, there is an algorithm\, due to Elkies\, that uses modular eq
uations to compute this isogeny explicitly. It is an essential tool in the
SEA point counting algorithm: using isogenies is superior to Schoof's ori
ginal idea of using endomorphisms. In this work\, we present the analogue
of Elkies' algorithm for Jacobians of genus 2 curves\, thus opening the wa
y to using isogenies in higher genus point counting.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean Kieffer imb":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean Kieffer
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:55e3c57c-bba7-459c-ae9e-90c640d2ac34
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20191001T100000
SUMMARY:An overview of isogeny algorithms
LOCATION:Salle 2
DESCRIPTION:Let $A$ be an abelian variety and $K$ a finite subgroup. We wi
ll discuss several approaches to compute the isogeny $A \\mapsto A/K$\, st
arting from Vélu's algorithm for elliptic curves\, and then the isogeny
theorem for theta functions\, Couveignes and Ezome's work on Jacobians of
curves\, and recent progress with David Lubicz.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert imb":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:64261f9b-6d6f-40c6-b8d1-cb647d6b06bd
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20191008T100000
SUMMARY:Computing Hilbert class fields of quartic CM fields using Complex
Multiplication
LOCATION:Salle 2
DESCRIPTION:The Hilbert class field $H_K(1)$ is the maximal unramified abe
lian extension of $K$. For imaginary quadratic number fields $K$\, it can
be generated using special values of certain analytic\, modular functions.
For quartic CM-fields $K$\, the corresponding construction yields only a
subfield of $H_K(1)$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jared Asuncion imb":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jared Asuncion
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:627e4a8c-d562-452a-ba7e-3954aede8ac5
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20191015T100000
SUMMARY:Cryptographie post-quantique à base de codes
LOCATION:Salle 2
DESCRIPTION:Nous nous proposons de faire un état de l'art et de discute
r l'état actuel de la cryptologie basée sur les codes. Nous nous int
éresserons à l'approche historique\, le paradigme de McEliece\, ains
i qu'à la méthodologie plus moderne\, initiée par Alekhnovich\, e
t inspirée de la cryptologie basée sur les réseaux suite aux trav
aux d'Ajtai et de Regev en particulier. Cette deuxième approche ne prÃ
©tendait pas à l'origine déboucher sur des systèmes de chiffreme
nt compétitifs\, mais présentait l'avantage théorique d'avoir des
preuves de sécurité bien identifiées et reconnues par la communa
uté de complexité algorithmique et de cryptologie théorique. Nous
détaillerons les principes de ces preuves de sécurité qui ne son
t pas accessibles de manière évidente dans la littérature. Nous m
ontrerons également en quoi il y a aujourd'hui convergence des deux app
roches du chiffrement basé sur les codes.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Gilles Zémor ":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Gilles Zémor
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:94157ff7-cc92-4af3-b2ef-6c656ac46d05
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20191022T100000
SUMMARY:Hacking session
LOCATION:Salle 2
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Développeurs LFANT IMB":MAILTO:null@mat
h.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Développeurs LFANT
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a4bd33f8-23a0-49c1-88c8-de2e3a21b9f4
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20191029T100000
SUMMARY:Hacking session
LOCATION:Salle 2
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Développeurs LFANT IMB":MAILTO:null@mat
h.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Développeurs LFANT
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:2411824a-263f-42e9-97d9-ed0c3229cd14
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20191105T100000
SUMMARY:Apéry-Like recursions and modular forms
LOCATION:Salle 2
DESCRIPTION:Following Zagier and Beukers\, we show that the sequences used
by Apery in his proofs of the irrationality of zeta(2) and zeta(3) are sp
ecial cases of more general sequences having surprisingly only integer val
ues\, and that many of these sequences can be parametrized by modular form
s. Following Almkwist and Zudilin\, we also explain that the degree three
sequences used for zeta(3) and generalizations can be automatically obtain
ed via a Clausen type hypergeometric identity from the degree two sequence
s used for zeta(2) and generalizations.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen imb":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:73b33674-0a30-44af-8a41-e126f134c733
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20191108T140000
SUMMARY:HDR defense: Cryptographie basée sur les corps quadratiques: cryp
tanalyse\, primitives et protocoles
LOCATION:Salle de conférences
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Guilhem Castagnos imb":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Guilhem Castagnos
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:cb801703-485a-4f67-ae23-f8ffde970314
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20191119T100000
SUMMARY:Exact Semidefinite Programming Bounds for Packing Problems
LOCATION:Salle 2
DESCRIPTION:Semidefinite Programming (SDP) is a powerful tool to obtain up
per bounds for packing problems. For example\, one can consider the kissin
g problem of the hemisphere in dimension 8 which asks for the maximal numb
er of pairwise non-overlapping spheres which can simultaneously touch a ce
ntral hemisphere in 8-dimensional Euclidean space. The E8 lattice gives a
kissing configuration of 183 points. Moreover\, using an SDP given by Bach
oc and Vallentin one gets an upper bound of 182.99999999996523. Hence\, th
e optimal value is 183. But how can we obtain the exact rational solution
of the SDP based on the floating point results given by the SDP solver?
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Maria Dostert EPFL":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Maria Dostert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:71b83c06-075e-4b93-9060-cbfc1522012c
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20191126T100000
SUMMARY:An LLL Algorithm for Module Lattices
LOCATION:Salle 1
DESCRIPTION:A lattice is a discrete subgroup (i.e.\, $\\mathbb Z$-module)
of $\\mathbb R^n$ (where $\\mathbb Z$ and $\\mathbb R$ are the sets of int
egers and real numbers). The LLL algorithm is a central algorithm to manip
ulate lattice bases. It takes as input a basis of a Euclidean lattice\, an
d\, within a polynomial number of operations\, it outputs another basis of
the same lattice but consisting of rather short vectors.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Alice Pellet-Mary ÉNS de Lyon":MAILTO:n
ull@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Alice Pellet-Mary
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:0514713b-4986-4131-a99c-f6513aa8f6c5
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20191210T100000
SUMMARY:Hacking session
LOCATION:Salle 2
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Développeurs LFANT IMB":MAILTO:null@mat
h.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Développeurs LFANT
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:8ade7431-8bd4-4217-b2e5-97f38cad0243
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20191210T100000
SUMMARY:Hacking session
LOCATION:Salle 2
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Développeurs LFANT IMB":MAILTO:null@mat
h.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Développeurs LFANT
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:85684376-cc8b-4738-a053-094bd4c3dc01
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20200114T100000
SUMMARY:Canonical Lift of Genus 2 Curves
LOCATION:Salle 385
DESCRIPTION:Let $\\mathcal{A}/\\mathbb{F}_q$ (with $q=p^n$) be an ordinary
abelian variety\, a classical result due to Lubin\, Serre and Tate says t
hat there exists a unique abelian variety $\\tilde{\\mathcal{A}}$ over $\\
mathbb{Z}_q$ such that the modulo $p$ reduction of $\\tilde{\\mathcal{A}}$
is $\\mathcal{A}$ and $End(\\tilde{\\mathcal{A}})\\cong End(\\mathcal{A})
$ as a ring. In 2000 T.Satoh introduced a point-counting algorithm on elli
ptic curves over $\\mathbb{F}_q$ based on canonical lift. In fact the acti
on of the lifted Verschiebung on the tangent space gives Frobenius eigenva
lues and hence the characteristic polynomial of the ordinary elliptic curv
es over $\\mathbb{F}_q$. We propose to extend the canonical lift algorithm
introduced by T.Satoh to genus 2 curves over finite fields\, using the mo
dular polynomials in dimension 2. We first prove the Kronecker condition i
n dimension 2 case and then succeed to lift the endomorphism ring of $\\ma
thcal{A}$ in dimension 2 case using a general lift algorithm of a $p$-tors
ion group of an ordinary abelian variety. These results provide an algorit
hm to compute the characteristic polynomial of a genus 2 curves in quasi-q
uadratic time complexity.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Abdoulaye Maiga IMB":MAILTO:null@math.u-
bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Abdoulaye Maiga
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:bd9a3085-81d4-41d5-a172-dffffcec8dcf
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20200128T100000
SUMMARY:Réseaux\, variétés abéliennes et courbes
LOCATION:Salle 385
DESCRIPTION:On expliquera d'abord comment la notion de *variété abÃ
©lienne complexe polarisée* possède une version euclidienne dans la
quelle on considère des triplets $(E\,\\Lambda\,v)$ d'un espace euclidi
en $E$\, d'un réseau $\\Lambda$ de $E$ et d'un élément $v$ de $\\
mathrm{GL}(E)$ tel que $v^2=-\\mathrm{Id}$ et $v(\\Lambda)\\subset\\Lambda
^*$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jacques Martinet IMB":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jacques Martinet
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:5b79795e-be12-4cfb-b3e9-c43e24c1611b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20200204T100000
SUMMARY:Une approche géométrique efficace pour le calcul d'espaces de Ri
emann-Roch : Algorithme et Complexité
LOCATION:Salle 385
DESCRIPTION:Le calcul effectif de bases d'espaces de Riemann-Roch intervie
nt dans de nombreux domaines pratiques\, notamment pour l'arithmétique
dans les jacobiennes de courbes ou dans des codes correcteurs d'erreurs al
gébraico-géométriques. Nous proposons une variante probabiliste d
e l'algorithme de Brill et Noether décrit par Goppa pour le calcul d'un
e base de l'espace de Riemann-Roch $L(D)$ associé à un diviseur $D$
d'une courbe projective plane nodale $C$ sur un corps parfait $k$ suffisam
ment grand.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Aude Le Gluher LORIA":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Aude Le Gluher
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ab24593d-7479-4624-8c92-5f25754ac884
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20200211T100000
SUMMARY:How to Get an Efficient yet Verified Arbitrary-Precision Integer L
ibrary
LOCATION:Salle 385
DESCRIPTION:We present a fully verified arbitrary-precision integer arithm
etic library designed using the Why3 program verifier. It is intended as a
verified replacement for the mpn layer of the state-of-the-art GNU Multi-
Precision library (GMP).
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Raphael Rieu-Helft Université Paris-Sud
":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Raphael Rieu-Helft
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:3d306e5f-6ec1-4a7e-85b5-ef5d5b8c1b6b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20200218T100000
SUMMARY:The ray class group of a "random" number field
LOCATION:Salle 385
DESCRIPTION:The Cohen–Lenstra–Martinet heuristics are a prob
abilistic model for the behaviour of class groups of number fields in natu
ral families. In this talk\, I will discuss a generalisation to ray class
groups. About 5 years ago\, Varma determined the average number of 3-torsi
on elements in the ray class group of K with respect to m\, when m is a fi
xed rational modulus\, and K runs through the family of imaginary quadrati
c or of real quadratic fields. Since then\, Bhargava has been challenging
the community to come up with a natural probabilistic model that would exp
lain the numbers obtained by Varma\, and to predict more general averages
in more general families of number fields. As I will explain in my talk\,
there turns out to be a very simple-minded way of doing so\, and also a mu
ch more conceptual one\, and they both turn out to be equivalent. The more
conceptual one involves an object that does not appear to have been treat
ed in the literature before\, but that is very natural: the Aralelov ray c
lass group of a number field. This is joint work with Carlo Pagano.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Alex Bartel University of Glasgow":MAILT
O:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Alex Bartel
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:f2772bd1-7337-49bb-8d56-ce4b5e5d65bb
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20200310T100000
SUMMARY:Harmonie et disparités dans le théorème de Chebotarev
LOCATION:Salle 385
DESCRIPTION:Étant donné une extension galoisienne de corps de nombr
es L/K\, le théorème de Chebotarev affirme l'équirépartition d
es éléments de Frobenius\, relatifs aux idéaux premiers non ramif
iés\, dans les classes de conjugaison de Gal(L/K). On présentera une
étude portant sur les variations du terme d'erreur dans le théorÃ
¨me de Chebotarev\, lorsque L/K parcourt certaines familles d'extensions.
On donnera une formule de transfert pour les fonctions classiques de dÃ
©compte des nombres (ou idéaux) premiers permettant de ramener la situ
ation à celle d'une extension des rationnels. On exposera enfin quelque
s conséquences à des problèmes de "type Linnik" et à l'analogu
e du phénomène de biais de Chebyshev dans les corps de nombres. L'ex
posé porte sur un travail commun avec D. Fiorilli.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Florent Jouve IMB":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Florent Jouve
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:e7cb30c3-d473-4983-bf03-e5c09ed14e41
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20200922T100000
SUMMARY:Modular Galois representations p-adically using Makdisi's moduli-f
riendly forms
LOCATION:Online
DESCRIPTION:We will present a p-adic method to compute Galois representati
ons attached to modular forms. This method compares very favourably to the
better-known complex-analytic approach. The main ingredient is the use of
“moduli-friendly" forms introduced by Makdisi\, which allow us to e
valuate modular forms at p-adic points of modular curves\, and thus to com
pute in the Jacobian of modular curves without writing down any equations
nor q-expansions.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Nicolas Mascot Trinity College Dublin":M
AILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Nicolas Mascot
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:abf0b79a-1a92-4170-abed-87d1590a389c
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20201013T100000
SUMMARY:Computing Galois groups over p-adic fields
LOCATION:Online
DESCRIPTION:We give an overview of the history of computing Galois groups
over p-adic fields\, with some diversions to recent progress over the rati
onal field. We focus on the "resolvent method\," a family of techniques to
compute Galois groups\, and present a recent algorithm to do this in gene
ral over p-adic fields\, the first of its kind. This algorithm greatly inc
reases the degree of polynomial that can be routinely handled\, and for ex
ample has been used to extend existing databases of Galois groups of p-adi
c fields to include all degree 18\, 20 and 22 extensions of the 2-adic fie
ld. The implementation and tables of results are available on the speaker'
s website.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Christopher Doris Heilbronn Institute an
d University of Bristol":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Christopher Doris
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:38abfa6e-b2df-4145-8f80-9c69d7de1c31
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20201103T100000
SUMMARY:Isomorphismes de représentations galoisiennes modulaires et graph
es
LOCATION:Online
DESCRIPTION:Dans cet exposé\, je vais expliquer comment tester efficace
ment et effectivement si deux représentations galoisiennes modulaires d
u groupe absolu de Galois des rationnels sont isomorphes. En particulier\,
je présenterai de nouvelles bornes optimales sur le nombre de traces
à tester. Je discuterai également brièvement des graphes des isom
orphismes\, des résultats associés sur les algèbres de Hecke et d
e la construction d'une base de données de représentations.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Samuele Anni Université Aix-Marseille":
MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Samuele Anni
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:b1c6324e-2d79-46f9-9444-4aa7ddd58814
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20201110T100000
SUMMARY:Calcul efficace des polynômes caractéristiques des p-courbures d
'un opérateur différentiel à coefficients entiers
LOCATION:Online
DESCRIPTION:Nous présentons un nouvel algorithme permettant de calculer
les polynômes caractéristiques des $p$-courbures d'un opérateur
différentiel à coefficients entiers pour tout $p$ premier inféri
eur à un entier $N$ donné\, en temps quasi-linéaire\, donc quasi-
optimal\, en $N$. L'algorithme présenté se base sur les travaux de A
. Bostan\, X. Caruso et E. Schost ramenant le calcul de cet invariant au c
alcul d'une factorielle de matrices\, ainsi que sur la technique de calcul
de factorielles développée par E. Costa\, R. Gerbicz et D. Harvey.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Raphaël Pagès IMB":MAILTO:null@math.u-
bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Raphaël Pagès
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:e69eb8a9-940d-4734-aa7f-3104d47fda6f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20201117T100000
SUMMARY:Calcium: computing in exact real and complex fields
LOCATION:Online
DESCRIPTION:Calcium is a C library for real and complex numbers in a form
suitable for exact algebraic and symbolic computation. Numbers are represe
nted as elements of fields $\\mathbb{Q}(a_1\,\\ldots\,a_n)$ where the exte
nsion numbers $a_k$ may be algebraic or transcendental. The system combine
s efficient field arithmetic with automatic construction of fields and ide
als of algebraic relations\, resulting in a practical computational model
of $\\mathbb{R}$ and $\\mathbb{C}$ in which equality is rigorously decidab
le for a large class of numbers which includes $\\overline{\\mathbb{Q}}$ a
s a subset.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Fredrik Johansson IMB":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Fredrik Johansson
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:220695e4-67d2-4d89-928a-fc14f83ab36d
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20201124T100000
SUMMARY:Recouvrements optimaux d'ensembles de Siegel tronqués par des bou
les euclidiennes
LOCATION:Online
DESCRIPTION:Étant donné un groupe algébrique $G$ agissant sur un
espace affine $V$\, il arrive que l'ensemble $V(\\mathbb{Z})/G(\\mathbb{Z
})$ des orbites entières paramètre des objets arithmétiques et so
it donc intéressant à énumérer. Une façon de s'y prendre co
nsiste à expliciter un domaine fondamental de l'action de $G(\\mathbb{Z
})$ sur $V(\\mathbb{R})$ et à y rechercher les points entiers. Pour cel
a\, on peut essayer de recouvrir ce domaine fondamental par une famille de
boules euclidiennes de rayon constant dont le cardinal soit du même or
dre de grandeur que le nombre de points entiers. Je montrerai comment mett
re en œuvre cette stratégie dans le cas simple de l'action à dro
ite de $\\mathrm{GL}_n$ sur $\\mathrm{M}_n$\, dont les orbites entières
paramètrent les sous-modules de $\\mathbb{Z}^n$\, et pour laquelle on
dispose de domaines fondamentaux approchés faciles à décrire\, Ã
savoir les ensembles de Siegel.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Anne-Edgar Wilke IMB":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Anne-Edgar Wilke
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6762769b-5465-46f5-bb5b-dab42c482820
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20201201T100000
SUMMARY:The conjugacy problem in $mathrm{GL}(n\, mathbb{Z})$
LOCATION:Online
DESCRIPTION:We consider the problem of deciding whether two matrices are c
onjugate. If the coefficient ring is a field\, this problem can be easily
solved by using the Jordan normal form or the rational canonical form. For
more general coefficient rings\, the situation becomes increasingly chall
enging\, both from a theoretical and a practical viewpoint. In this talk\,
we show how the conjugacy problem for integer matrices can be efficiently
decided using techniques from group and number theory. This is joint work
with Bettina Eick and Eamonn O'Brien.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Tommy Hofmann Saarland University":MAILT
O:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Tommy Hofmann
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1cc85342-3c65-4192-9803-22505752d1db
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20201208T100000
SUMMARY:Zéros réels de fonctions L d'Artin et biais de Chebyshev dans le
s corps de nombres
LOCATION:Salle 385
DESCRIPTION:Le biais de Chebyshev est un phénomène qui a été
étudié tout d'abord dans le cadre des "courses de nombres premiers"
(Rubinstein et Sarnak\, 1994) pour expliquer la prédominance apparente
des nombres premiers congrus à 3 mod 4 par rapport à ceux qui sont c
ongrus à 1 mod 4. Ces courses de nombres premiers ont été gén
éralisées notamment dans le contexte des corps de nombres par Ng en
2000. Dans des travaux récents\, Fiorilli et Jouve ont étudié le
biais de Chebyshev dans des familles d'extensions de corps de nombres\, et
mis en évidence des comportements limites de type "grandes déviatio
ns" et "théorème central limite". Dans le travail présenté\, j
e mets en évidence l'influence considérable qu'ont certains zéros
réels de fonctions L d'Artin sur le biais de Chebyshev dans des extens
ions particulières de corps de nombres.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Alexandre Bailleul ENS Lyon":MAILTO:null
@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Alexandre Bailleul
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6cdad3ed-5740-431d-b4ac-1d37ac9616bd
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20201215T100000
SUMMARY:Équations différentielles $p$-adiques pour le calcul d'isogénie
s en.petite caractéristique
LOCATION:Online
DESCRIPTION:On présente une méthode effective de calcul sur les $p$-
adiques d’isogénies entre courbes elliptiques et Jacobiennes de
courbes hyperelliptiques de petit genre. Une application importante est le
cas des courbes définies sur un corps fini de petite caractéristiqu
e\, qui peut être résolu par relèvement dans les $p$-adiques. Not
re algorithme repose sur la résolution d’équations différe
ntielles avec un bon contrôle de perte de précision. Son analyse est
basée sur la théorie de la précision différentielle dévelo
ppée par Caruso\, Roe et Vaccon.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Elie Eid Université de Rennes":MAILTO:n
ull@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Elie Eid
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:da3ac5f0-c061-45e3-a4e1-029523c142d5
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210112T100000
SUMMARY:On the hardness of code equivalence problems in rank metric
LOCATION:Online
DESCRIPTION:In recent years\, the notion of rank metric in the context of
coding theory has known many interesting developments in terms of applicat
ions such as space time coding\, network coding or public key cryptography
. These applications raised the interest of the community for theoretical
properties of this type of codes\, such as the hardness of decoding in ran
k metric or better decoding algorithms. Among classical problems associate
d to codes for a given metric\, the notion of code equivalence has always
been of the greatest interest. In this talk\, we discuss the hardness of t
he code equivalence problem in rank metric for $\\mathbb F_{q^m}$--linear
and general rank metric codes.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Alain Couvreur LIX -- Inria Saclay":MAIL
TO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Alain Couvreur
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:02d0a64b-195e-4428-b2f5-6663b5025097
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210119T100000
SUMMARY:Une introduction aux circuits quantiques et au ZX-calcul
LOCATION:Online
DESCRIPTION:L'informatique quantique est de plus en plus un sujet brûla
nt\, car elle promet bien des avantages\, que ça soit pour la complexit
é de ses algorithmes\, ou pour ce qu'elle permet en cryptographie. Dans
cet exposé\, nous allons d'abord voir les circuits quantiques \;:
le modèle habituellement utilisé par les chercheurs et les ingéni
eurs pour décrire des processus quantiques. Nous nous intéresserons
à une question fondamentale liée à ces circuits\, celle de la com
plétude d'une théorie équationnelle. Nous présenterons ensuite
le ZX-Calcul\, un modèle issu de la théorie des catégories\, qui
répond\, lui\, positivement à cette même question.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Renaud Vilmart LSV -- Inria Saclay":MAIL
TO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Renaud Vilmart
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:aba5d2ac-7571-47ed-a8ec-24c6aca18669
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210126T100000
SUMMARY:The Fundamental Theorem of Tropical Partial Differential Algebraic
.Geometry
LOCATION:Online
DESCRIPTION:Given a partial differential equation (PDE)\, its solutions ca
n be difficult\, if not impossible\, to describe. The purpose of the Funda
mental theorem of tropical (partial) differential algebraic geometry is to
extract from the equations certain properties of the solutions. More prec
isely\, this theorem proves that the support of the solutions in $k[[t_1\,
\\cdots\, t_m]]$ (with $k$ a field of characteristic zero) can be obtaine
d by solving a so-called tropicalized differential system.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Mercedes Haiech Université Rennes 1":MA
ILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Mercedes Haiech
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:43be30be-130b-452f-a267-532977074f64
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210202T100000
SUMMARY:Isogenous hyperelliptic and non-hyperelliptic Jacobians with maxim
al complex multiplication
LOCATION:Online
DESCRIPTION:We analyze complex multiplication for Jacobians of curves of g
enus 3\, as well as the resulting Shimura class groups and their subgroups
corresponding to Galois conjugation over the reflex field. We combine our
results with numerical methods to find CM fields $K$ for which there exis
t both hyperelliptic and non-hyperelliptic curves whose Jacobian has compl
ex multiplication by $\\mathbb{Z}_K$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bogdan Dina Ulm University":MAILTO:null@
math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bogdan Dina
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:92b0403b-0080-4f8a-9121-ef597b31e84d
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210302T100000
SUMMARY:Explicit construction and parameters of projective toric codes
LOCATION:Online
DESCRIPTION:Toric codes\, introduced by Hansen in 2002\, generalize (weigh
ted) Reed-Muller codes on other toric varieties than projective spaces. Th
ey consist of evaluation codes of monomials at tuples of non-zero coordina
tes\, which correspond to the points on the dense torus contained in the a
ssociated toric variety. Our aim is to ‘projectivise’ these c
odes\, in the same spirit that turns a Reed-Muller codes into a projective
one: we consider codes obtained by evaluating global sections on the whol
e set of the rational points of a toric variety. We focus on simplicial to
ric varieties\, which come with a nice quotient description\, and we give
an explicit construction of projective codes on them\, as well as a combin
atorial way to determine their parameters. 'Projectivizing' toric codes op
ens new possibilities of getting codes with excellent parameters\, by exte
nding some champion classical toric codes geometrically.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jade Nardi Inria Saclay\, LIX":MAILTO:nu
ll@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jade Nardi
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:938a805e-488d-45c8-9323-5c1f3997bf0d
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210309T100000
SUMMARY:Bornes de Sturm pour des formes automorphes sur les corps de fonct
ions
LOCATION:Online
DESCRIPTION:Les bornes de Sturm indiquent combien de coefficients de Fouri
er successifs suffisent à déterminer une forme modulaire. Pour les f
ormes modulaires classiques\, elles fournissent aussi des bornes sur le no
mbre d'opérateurs de Hecke engendrant l'algèbre du même nom. Cet
exposé propose d'étudier la situation pour certaines formes automorp
hes\, dites de Drinfeld\, sur les corps de fonctions. Il s'agit d'un trava
il en commun avec Fu-Tsun Wei (National Tsing-Hua University\, Taïwan).
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Cécile Armana LMB\, Université de Fran
che-Comté":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Cécile Armana
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:3db5e93c-bd72-462c-8195-b0cc4ced7b46
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210316T100000
SUMMARY:Deterministic computation of the characteristic polynomial in the
time of matrix multiplication
LOCATION:Online
DESCRIPTION:This talk describes joint work with Clément Pernet on an al
gorithm which computes the characteristic polynomial of a matrix over a fi
eld within the same asymptotic complexity\, up to constant factors\, as th
e multiplication of two square matrices. Previously\, this was only achiev
ed by resorting to genericity assumptions or randomization techniques\, wh
ile the best known complexity bound with a general deterministic algorithm
was obtained by Keller-Gehrig in 1985 and involves logarithmic factors. T
he new algorithm computes more generally the determinant of a univariate p
olynomial matrix in reduced form.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Vincent Neiger Université de Limoges":M
AILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Vincent Neiger
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:e75b764e-07e5-4101-ab57-0f5cd0d308ca
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210316T100000
SUMMARY:Deterministic computation of the characteristic polynomial in the
time of matrix multiplication
LOCATION:Online
DESCRIPTION:This talk describes joint work with Clément Pernet on an al
gorithm which computes the characteristic polynomial of a matrix over a fi
eld within the same asymptotic complexity\, up to constant factors\, as th
e multiplication of two square matrices. Previously\, this was only achiev
ed by resorting to genericity assumptions or randomization techniques\, wh
ile the best known complexity bound with a general deterministic algorithm
was obtained by Keller-Gehrig in 1985 and involves logarithmic factors. T
he new algorithm computes more generally the determinant of a univariate p
olynomial matrix in reduced form.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Vincent Neiger Université de Limoges":M
AILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Vincent Neiger
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6faed1a7-4d92-42c3-a0a8-5f4a65abc9c0
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210323T100000
SUMMARY:Recherche de points entiers sur une variété modulaire de dimensi
on 3
LOCATION:Online
DESCRIPTION:La détermination effective des points entiers sur des vari
étés algébriques est un problème difficile\, surtout en dimens
ion plus grande que 1. Dans cet exposé\, je présenterai brièvemen
t deux approches naturelles pour les points entiers qui permettent dans d
es cas favorables de tous les trouver. En cherchant des raffinements de ce
s méthodes\, on arrive à des problèmes combinatoires intéressa
nts\, que je mettrai en valeur dans le cas précis d'une variété "
modulaire" de dimension 3\, qu'on peut définir par une équation quar
tique dans $\\mathbb{P}^4$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Samuel Le Fourn Institut Fourier\, Unive
rsité Grenoble Alpes":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Samuel Le Fourn
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a7991f2b-c4a0-47c4-aa6f-353b3cc1828a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210330T100000
SUMMARY:Dynamiques des algorithmes de fraction continue multidimensionnels
LOCATION:Online
DESCRIPTION:Motivés par la richesse de l'algorithme de Gauss qui permet
de calculer efficacement les meilleurs approximation d'un nombre réel
par des rationnels\, beaucoup de mathématiciens ont proposé des gÃ
©néralisations de ces algorithmes pour approximer des vecteurs de dime
nsion supérieure à 1. Citons pour exemple celui de Poincaré intro
duit à la fin du 19e siècle ou ceux de Brun et Selmer à la moiti
é du 20e siècle.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Charles Fougeron IRIF\, Université de P
aris":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Charles Fougeron
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:7b82e254-a233-43ae-8bcd-82e59c92a42a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210406T100000
SUMMARY:Numerical experiments with plectic Stark--Heegner points
LOCATION:Online
DESCRIPTION:Let $E/F$ be an elliptic curve defined over a number field $F$
\, and let $K/F$ be a quadratic extension. If the analytic rank of $E(K)$
is one\, one can often use Heegner points (or the more general Darmon poin
ts) to produce (at least conjecturally) a nontorsion generator of $E(K)$.
If the analytic rank of $E(K)$ is larger than one\, the problem of constru
cting algebraic points is still very open. In very recent work\, Michele F
ornea and Lennart Gehrmann have introduced certain $p$-adic quantities tha
t may be conjecturally related to the existence of these points. In this t
alk I will explain their construction\, and illustrate with some numerical
experiments that we have been able to carry out that support their conjec
ture. This is joint work with Michele Fornea and Xevi Guitart.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Marc Masdeu Universitat Autònoma de Bar
celona":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Marc Masdeu
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:d391959a-b14c-4b50-b8f0-4697022d25f3
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210427T100000
SUMMARY:Property (FA) of the unit group of $2$-by-$2$ matrices over an ord
er in a quaternion algebra
LOCATION:Online
DESCRIPTION:We study property (FA) and its hereditary version for unit gro
ups of $2$-by-$2$ matrices over orders in totally definite quaternion alge
bras with rational centres. In particular we consider the three matrix rin
gs over totally definite rational quaternion algebras that can appear as W
edderbrun-Artin components of a group ring $\\mathbb{Q}G$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Ann Kiefer Luxembourg Centre for Educati
onal Testing":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Ann Kiefer
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:e891b956-69f7-4d3c-8d33-cb2dfeadda3d
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210504T100000
SUMMARY:Explicit isogenies of prime degree over quadratic fields
LOCATION:Online
DESCRIPTION:Let $K$ be a quadratic field which is not an imaginary quadrat
ic field of class number one. We describe an algorithm to compute a supers
et of the set of primes $p$ for which there exists an elliptic curve over
$K$ admitting a $K$-rational $p$-isogeny. Combining this algorithm with re
cent work on the determination of quadratic points on low-genus modular cu
rves\, we determine - conditional upon the Generalised Riemann Hypothesis
- the above set of isogeny primes for several quadratic fields\, providing
the first such examples after Mazur's 1978 determination for $K = \\mathb
b{Q}$. We will give a live demo of the Sage and PARI/GP implementations of
the algorithm.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Barinder Banwait Harish-Chandra Research
Institute":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Barinder Banwait
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:0e4aac1e-2f70-49c6-80d6-0722067eaf5f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210511T100000
SUMMARY:On algorithms for solving Euclidean lattice problems in cryptograp
hy
LOCATION:Online
DESCRIPTION:In this talk\, we will try to review the state-of-the-art of t
he algorithms for solving the Euclidean lattice problems underlying crypto
graphy. In more details\, this talk contains two parts. In the first part\
, we will focus on the lattice problems such as approximate Shortest Vecto
r Problem (approx-SVP) and the lattice reduction algorithms as the best kn
own solving algorithms so far. In particular\, I will present an improved
enumeration-based lattice reduction algorithm\, which is shown to be (pote
ntially) relevant to cryptanalysis. In the second part\, we will instead c
onsider a quantum problem that is computationally equivalent to approx-SVP
. By directly solving a quantum problem\, we may expect to have a more pow
erful use of the quantum computation. However\, the best known algorithms
for solving approx-SVP via solving this quantum problem\, is not better th
an lattice reduction yet.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Weiqiang Wen Inria Rennes\, Irisa":MAILT
O:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Weiqiang Wen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ebbdd82b-6131-40d8-b3a2-5562f08b10f6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210518T100000
SUMMARY:Computing Murphy-alpha in the special tower number field sieve alg
orithm and applications to pairing-based cryptography
LOCATION:Online
DESCRIPTION:Pairings on elliptic curves are involved in signatures\, NIZK\
, and recently in blockchains (ZK-SNARKS). These pairings take as input tw
o points on an elliptic curve $E$ over a finite field\, and output a value
in an extension of that finite field. Usually for efficiency reasons\, th
is extension degree is a power of 2 and 3 (such as 12\, 18\, 24)\, and mor
eover the characteristic of the finite field has a special form. The secur
ity relies on the hardness of computing discrete logarithms in the group o
f points of the curve and in the finite field extension.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Aurore Guillevic Inria Nancy\, Loria":MA
ILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Aurore Guillevic
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ed0ba001-847d-4760-8d75-23e8d1e6dfb6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210525T100000
SUMMARY:Quelques conséquences du programme de Mazur sur la cryptographie
LOCATION:Online
DESCRIPTION:Les algorithmes de factorisation d'entiers et ceux de calcul d
e logarithmes discrets\, adaptés aux tailles cryptographiques\, ont deu
x étapes pertinentes pour notre exposé : la sélection polynomiale
et la cofactorisation. La première consiste à sélectionner deux
polynômes homogènes $F(x\,y)$ et $G(x\,y)$ dans $\\mathbb{Z}[x\,y]$
tels que les entiers de l'ensemble $\\{F(a\,b)G(a\,b)\\mid a\,b\\in\\text{
un rectangle }\,\\gcd(a\,b)=1 \\}$ contiennent le plus possible d'entiers
$B$-friables (ayant tous les facteurs premiers inférieurs à $B$). L
a deuxième consiste à factoriser des entiers de la forme $F(a\,b)$ e
t $G(a\,b)$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Razvan Barbulescu CNRS\, IMB":MAILTO:nul
l@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Razvan Barbulescu
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:f5a0b635-9b2e-4533-bc3c-681499f71ca9
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210601T100000
SUMMARY:Présentation de l'équipe LFANT pour les stagiaires
LOCATION:Online
DESCRIPTION:Cette séance spéciale est dédiée à l'accueil de
s stagiaires dans l'équipe LFANT. Après une présentation génÃ
©rale de l'équipe\, nous présenterons deux logiciels que nous dé
veloppons : PARI/GP et Arb.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge\, Bill Allombert\, Fredrik
Johansson Inria\, CNRS\, Inria":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge\, Bill Allombert\, Fredrik Johansson
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:fe7059ba-bfb7-48af-861c-76198d18d65e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210608T100000
SUMMARY:Optimization of the scalar complexity of Chudnovsky^2 multiplicati
on algorithms in finite fields
LOCATION:Online
DESCRIPTION:We propose several constructions for the original multiplicati
on algorithm of D.V. and G.V. Chudnovsky in order to improve its scalar co
mplexity. We highlight the set of generic strategies who underlay the opti
mization of the scalar complexity\, according to parameterizable criteria.
As an example\, we apply this analysis to the construction of type ellipt
ic Chudnovsky2 multiplication algorithms for small extensions. As a case s
tudy\, we significantly improve the Baum-Shokrollahi construction for mult
iplication in F256/F4.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Stéphane Ballet I2M\, Université Aix-M
arseille":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Stéphane Ballet
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1085c8c9-14aa-4e24-a7bc-f3a2b6af9563
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210615T100000
SUMMARY:Corps de modules des courbes de genre 2 à Jacobienne décomposée
LOCATION:Online
DESCRIPTION:Nous nous intéresserons aux de courbes de genre 2 dont la J
acobienne est géométriquement le produit de deux courbes elliptiques
avec multiplication complexe par le même ordre (maximal). Nous propose
rons un algorithme permettant de compter combien d'entre elles ont pour co
rps de modules Q. Pour cela nous développerons une équivalence de ca
tégories entre certaines variétés abéliennes polarisées et
des réseaux hermitiens. Il s'agit d'une généralisation d'un artic
le de A. Gélin\, E. Howe et C. Ritzenthaler de 2018 dans lequel la Jaco
bienne est le carré d'une même courbe elliptique.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Fabien Narbonne IRMAR\, Université de R
ennes":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Fabien Narbonne
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:7465bda6-6cd7-4ad8-993d-72e1dcbe738a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210622T100000
SUMMARY:Shifted powers in Lucas-Lehmer sequences
LOCATION:Online
DESCRIPTION:The explicit determination of perfect powers in (shifted) non-
degenerate\, integer\, binary linear recurrence sequences has only been ac
hieved in a handful of cases. In this talk\, we combine bounds for linear
forms in logarithms with results from the modularity of elliptic curves de
fined over totally real fields to explicitly determine all shifted powers
by two in the Fibonacci sequence. A major obstacle that is overcome in thi
s work is that the Hilbert newspace which we are interested in has dimensi
on 6144. We will focus on how this space is computationally handled with r
espect to the underlying Diophantine equation. This is joint work with Mik
e Bennett (UBC) and Samir Siksek (Warwick).
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Vandita Patel University of Manchester":
MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Vandita Patel
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ce119de0-0d79-4788-a79d-58d5a9c705e6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210629T100000
SUMMARY:An algebraic approach to the Rank Support Learning problem
LOCATION:Online
DESCRIPTION:Rank-metric code-based cryptography relies on the hardness of
decoding a random linear code in the rank metric. The Rank Support Learnin
g problem (RSL) is a variant where an attacker has access to N decoding in
stances whose errors have the same support and wants to solve one of them.
This problem is for instance used in the Durandal signature scheme. In th
is talk\, we will present a new algebraic attack on RSL. We build upon Bar
det et al.\, Asiacrypt 2020\, where similar techniques are used to solve M
inRank and RD. However\, our analysis is simpler and overall our attack re
lies on very elementary assumptions compared to standard Gröbner bases
attacks. In particular\, our results show that key recovery attacks on Dur
andal are more efficient than was previously thought. This is joint work w
ith Magali Bardet.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pierre Briaud Inria Paris":MAILTO:null@m
ath.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pierre Briaud
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:3cdfb48c-75dd-498f-a98c-6589ec212ce1
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210706T100000
SUMMARY:The Inverse Jacobian problem
LOCATION:Online
DESCRIPTION:To an algebraic curve $C$ over the complex numbers one can ass
ociate a non-negative integer $g$\, the genus\, as a measure of its comple
xity. One can also associate to $C$\, via complex analysis\, a $g\\times g
$ symmetric matrix $\\Omega$ called period matrix. Because of the natural
relation between $C$ and $\\Omega$\, one can obtain information about one
by studying the other. Therefore\, it makes sense to consider the inverse
problem: Given a period matrix $\\Omega$\, can we compute a model for the
associated curve $C$?
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Anna Somoza IRMAR\, Université de Renne
s 1":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Anna Somoza
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c712cd35-ed69-44dd-9ca5-349951070902
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20210713T150000
SUMMARY:Équations modulaires en dimension supérieure\, applications au c
alcul d'isogénies et au comptage de points
LOCATION:Salle de conférences
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean Kieffer IMB":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean Kieffer
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:5f9a948c-9f8f-41f9-8065-3373c2695659
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20211005T100000
SUMMARY:Algebraic values of the hypergeometric function
LOCATION:Salle 2
DESCRIPTION:In this talk\, I will study the general problem of when the va
lue of the hypergeometric function $F(a\,b\;c\;z)$ is algebraic\, assuming
$a$\,$b$\,$c$\, and $z$ rational. The results involve modular forms and f
unctions\, complex multiplication\, Shimura curves\, and computer searches
.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen IMB":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:fc297019-b4da-406b-b8ce-8870775021b5
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20211012T100000
SUMMARY:Revisiter l'algorithme de Satoh de comptage de points en petite ca
ractéristique par relèvement canonique
LOCATION:Salle 2
DESCRIPTION:L'algorithme de Satoh de comptage de points sur les courbes el
liptiques permet d'obtenir (après des améliorations de Harvey) une c
omplexité quasi-quadratique en le degré pour une (petite) caracté
ristique fixée $p$. Dans cet exposé je passerai en revue plusieurs v
ariantes de cet algorithme et ses extensions aux variétés abélien
nes. J'expliquerai ensuite comment on peut grandement simplifier l'implÃ
©mentation de cet algorithme. L'implémentation dans Pari/GP du nouvel
algorithme produit un gain d'un facteur 30 Ã la fois de temps de calcul
et de consommation mémoire.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert IMB":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:83d680dc-2fbe-4708-ae4c-15169eb07379
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20211109T100000
SUMMARY:Sampling relatively near-prime ideals
LOCATION:Salle 2
DESCRIPTION:We show a method to sample an element alpha from a given ideal
I\, such that their quotient ideal (alpha)/I is a (possibly large) prime
times a smooth number ('near-prime') with reasonable probability. This met
hod consists of 'randomizing' the ideal I by multiplying it with small pri
mes (yielding J) and consequently sampling the element alpha from this ran
domized ideal J intersected with a large box. The probability that the quo
tient (alpha)/J is prime (i.e.\, that the quotient (alpha)/I is a near-pri
me) is tightly related to density results on prime ideals (prime ideal the
orem). As an application we show an efficient way to compute power residue
symbols for varying degree number fields.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Koen de Boer CWI Amsterdam":MAILTO:null@
math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Koen de Boer
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:17063a44-24d3-4cd6-b566-b0e42f47997a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20211116T100000
SUMMARY:SQISign: Compact Post-Quantum Signature from Quaternions and Isoge
nies
LOCATION:Salle 2
DESCRIPTION:We will present the signature scheme SQISign\, (for Short Quat
ernion and Isogeny Signature) exploiting isogeny graphs of supersingular e
lliptic curves. The signature and public key sizes combined are an order o
f magnitude smaller than all other post-quantum signature schemes. Its eff
icient implementation and security analysis open new research challenges.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Benjamin Wesolowski CNRS\, IMB":MAILTO:n
ull@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Benjamin Wesolowski
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:9ec0ef03-c863-40ec-8d17-083077352c73
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20211123T100000
SUMMARY:Norm relations and class group computations
LOCATION:Salle 2
DESCRIPTION:When $L/K$ is a Galois extension of number fields with Galois
group $G$\, some invariants of $L$ can be related to those of its proper s
ubfields. I will present some old and some new such relations\, and an app
lication to the computation of class groups of some large number fields. T
his is joint work with Jean-François Biasse\, Claus Fieker and Tommy Ho
fmann.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Aurel Page IMB":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Aurel Page
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6aa6e39f-8968-4f1b-8863-7e4626ffc1fb
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20211130T100000
SUMMARY:The partial Vandermonde knapsack problem
LOCATION:Salle 2
DESCRIPTION:In my seminar I will do an introduction to the concept of esse
ntial dimension: roughly speaking\, the essential dimension is a measure o
f how many independent parameters we need to describe some algebraic objec
t. The concept of essential dimension was introduced by Buhler and Reichst
ein in 1995 and it is linked to an algebraic version of Hilbert's 13th pro
blem. For a finite group $G$\; the essential dimension measures how much o
ne can compress a faithful representation of $G$. When $G$ is the symmetri
c group $S_n$ the essential dimension tells us how many independent parame
ters we need to write a generic polynomial of degree $n$ on a field $k$ of
characteristic zero\; equivalently\, the essential dimension of $S_n$ com
putes the number of parameters needed to write a generating polynomial for
separable field extensions of degree $n$. This is still an open problem f
or $n geq 8. Suprisingly\, the analogue problem for inseparable field exte
nsions has been solved explicitely.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Katharina Boudgoust IRISA EMSEC\, Rennes
":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Katharina Boudgoust
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:bc4a7423-6f96-4baa-8307-1d3b49664325
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20211130T100000
SUMMARY:The partial Vandermonde knapsack problem
LOCATION:Salle 2
DESCRIPTION:This work contributes in the field of lattice-based cryptograp
hy\, a research domain of public key cryptography that was initiated at th
e end of the 1990s by two different branches. On the one had\, there have
been proposals benefiting from strong theoretical connections to presumed
hard worst-case lattice problems\, leading to the development of public ke
y cryptography based on the SIS (Short Integer Solution) and LWE (Learning
With Errors) problems. On the other hand\, very efficient schemes basing
their security on average-case structured lattice problems have been intro
duced\, the most popular among them is the NTRU encryption scheme.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Katharina Boudgoust IRISA EMSEC\, Rennes
":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Katharina Boudgoust
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a94bbeac-080c-45d7-aa8b-7c0458d91aef
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20211207T100000
SUMMARY:Log-S-unit lattices using Explicit Stickelberger Generators to sol
ve Approx Ideal-SVP
LOCATION:Salle 386
DESCRIPTION:The Twisted-PHS algorithm to solve Approx-SVP for ideal lattic
es on any number field\, based on the PHS algorithm by Pellet-Mary\, Hanro
t and Stehlé in 2019\, was introduced in 2020. The authors performed ex
periments for prime conductors cyclotomic fields of degrees at most 70\, r
eporting exact approximation factors reached in practice. The main obstacl
e for these experiments is the computation of a log-S-unit lattice\, which
requires classical subexponential time.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Olivier Bernard IRISA EMSEC\, Rennes":MA
ILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Olivier Bernard
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:7680da36-4926-4a10-9fc9-8bf011c5a2f6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20211214T100000
SUMMARY:Un phénomène de concentration en géométrie combinatoire
LOCATION:Online
DESCRIPTION:Le type d'ordre d'une séquence de points du plan est une g
énéralisation de la permutation associée à une séquence de
nombres réels. Cette structure combinatoire encode de nombreuses propri
étés géométriques de la séquence de points\, par exemple le
treillis des faces de son enveloppe convexe\, ou encore les triangulation
s qu'elle supporte.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Xavier Goaoc Université de Lorraine\, L
ORIA":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Xavier Goaoc
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:71b94d3b-777a-4413-90c0-16e7bd0757a3
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220104T100000
SUMMARY:New data structure for univariate polynomial approximation and app
lications to root isolation\, numerical multipoint evaluation\, and other
problems
LOCATION:Online
DESCRIPTION:We present a new data structure to approximate accurately and
efficiently a polynomial $f$ of degree $d$ given as a list of coefficients
. Its properties allow us to improve the state-of-the-art bounds on the bi
t complexity for the problems of root isolation and approximate multipoint
evaluation. This data structure also leads to a new geometric criterion t
o detect ill-conditioned polynomials\, implying notably that the standard
condition number of the zeros of a polynomial is at least exponential in t
he number of roots of modulus less than $\\frac{1}{2}$ or greater than $2$
.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Guillaume Moroz Inria\, LORIA":MAILTO:nu
ll@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Guillaume Moroz
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:36ecd157-3ae0-4330-8b34-2595a66beae8
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220125T100000
SUMMARY:Parity of ranks of abelian surfaces
LOCATION:Online
DESCRIPTION:Let $K$ be a number field and $A/K$ an abelian surface. By the
Mordell-Weil theorem\, the group of $K$-rational points on $A$ is finitel
y generated and as for elliptic curves\, its rank is predicted by the Birc
h and Swinnerton-Dyer conjecture. A basic consequence of this conjecture i
s the parity conjecture: the sign of the functional equation of the $L$-se
ries determines the parity of the rank of $A/K$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Céline Maistret University of Bristol":
MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Céline Maistret
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:179d9f01-3507-429f-8315-9b69d75decf3
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220208T100000
SUMMARY:Reduction type of hyperelliptic curves in terms of the valuations
of their invariants.
LOCATION:Online
DESCRIPTION:In this talk we will first review the classical criteria to de
termine the (stable) reduction type of elliptic curves (Tate) and of genus
2 curves (Liu) in terms of the valuations of some particular combinations
of their invariants. We will also revisit the theory of cluster pictures
to determine the reduction type of hyperelliptic curves (Dokchitser's et a
l.). Via Mumford theta constants and Takase and Tomae's formulas we will b
e able to read the cluster picture information by looking at the valuation
s of some (Ã la Tsuyumine) invariants in the genus 3 case. We will also
discuss the possible generalization of this strategy for any genus and so
me related open questions.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Elisa Lorenzo Garcia Université de Neuc
hâtel":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Elisa Lorenzo Garcia
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:28297f89-5353-48f1-a963-36684cd55f3b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220308T100000
SUMMARY:Calcul d'espaces de Riemann-Roch pour les codes géométriques
LOCATION:Online
DESCRIPTION:Les codes de Reed-Solomon sont largement utilisés pour repr
ésenter des données sous forme de vecteurs\, de sorte que les donnÃ
©es peuvent être récupérées même si certaines coordonné
es des vecteurs sont corrompues. Ces codes ont de nombreuses propriétÃ
©s. Leurs paramètres sont optimaux. Ils permettent de reconstruire des
coordonnées qui ont été effacées. Ils sont compatibles avec l
'addition et la multiplication de données. Néanmoins\, ils souffrent
de certaines limitations. Notamment\, la taille de stockage des coordonn
ées des vecteurs augmente de manière logarithmique avec le nombre de
coordonnées. Les codes dits géométriques généralisent les
codes de Reed-Solomon en bénéficiant des mêmes propriétés\,
tout en étant libres de ces limitations. Par conséquent\, l'utilisa
tion de codes géométriques apporte des gains de complexité\, et s
'avère utile dans plusieurs applications telles que le calcul distribu
é sur les secrets et les preuves zero-knowledge. Les codes géomét
riques sont construits en évaluant des familles de fonctions\, appelÃ
©es espaces de Riemann-Roch\, en les points rationnels d'une courbe. Il s
'ensuit que le calcul de ces espaces est crucial pour la mise en Å“uvre
des codes géométriques. Dans cet exposé\, je présenterai un t
ravail récent en collaboration avec S. Abelard\, A. Couvreur et G. Lece
rf sur le calcul effectif des bases des espaces de Riemann-Roch de courbes
. Après avoir révisé l'état de l'art sur le sujet\, je discute
rai des idées à la base de notre algorithme\, en particulier la thÃ
©orie de Brill-Noether et l'utilisation des expansions de Puiseux. Les co
urbes utilisées dans la construction des codes géométriques sont
pour la plupart limitées à celles pour lesquelles les bases de Riema
nn-Roch sont déjà connues. Ce nouveau travail et ceux qui suivront\,
permettront la construction de codes géométriques à partir de co
urbes plus générales.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Elena Berardini Télécom Paris":MAILTO:
null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Elena Berardini
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:39659fbe-ad31-46cf-8d9b-6d45c5d5c19e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220315T100000
SUMMARY:Cryptanalyse du protocole OSIDH
LOCATION:Salle 2
DESCRIPTION:Oriented Supersingular Isogeny Diffie-Hellman (OSIDH) est un
échange de clé post-quantique proposé par Leonardo Colò et Dav
id Kohel en 2019. La construction repose sur l’action du groupe de
classe d’un ordre quadratique imaginaire sur un espace de courbes e
lliptiques supersingulières et peut donc être vue comme une génÃ
©ralisation du célèbre échange de clé à base d’isog
énies CSIDH. Cependant\, OSIDH est très différent de CSIDH dâ€
™un point de vue algorithmique parce qu’OSIDH utilise des groupes
de classe plus structurés que CSIDH. Comme l’ont reconnu ColÃ
² et Kohel eux-mêmes\, cela rend OSIDH plus vulnérable aux attaques
. Pour contourner cette faiblesse\, ils ont proposé une façon ingÃ
©nieuse d’effectuer l’échange de clé en échangeant
de l’information sur l’action du groupe de classe au voisin
age des courbes publiques\, et ont conjecturé que cette information add
itionnelle n’impacterait pas la sécurité.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pierrick Dartois Corps des mines\, Renne
s 1":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pierrick Dartois
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ed19877f-a32a-4e56-a320-c7618923f4c2
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220322T100000
SUMMARY:Schémas de Newton certifiés pour l'évaluation des fonctions th
êta en petit genre
LOCATION:Salle 2
DESCRIPTION:Les fonctions thêta permettent de relier les points de vue
algébrique et analytique dans l'étude des variétés abélienn
es: ce sont des formes modulaires de Siegel qui fournissent des coordonnÃ
©es sur ces variétés et leurs espaces de modules. Rendre ce lien ef
fectif nécessite un algorithme efficace d'évaluation de ces fonction
s thêta en un point. Dupont\, dans sa thèse (2006)\, a décrit un
algorithme heuristique basé sur la moyenne arithmético-géométr
ique (AGM) et un schéma de Newton pour évaluer certaines fonctions t
hêta en genre 1 et 2 en temps quasi-linéaire en la précision. Le
but de cet exposé est de montrer que l'on peut en fait obtenir un algor
ithme certifié dont la complexité est uniforme. Je discuterai éga
lement des obstacles restants pour généraliser ce résultat en dim
ension supérieure.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean Kieffer Harvard University":MAILTO:
null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean Kieffer
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:ad903ac6-1100-4c30-a8f8-d8d14d3c249b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220329T100000
SUMMARY:Constructing all genus 2 curves with supersingular Jacobian
LOCATION:Online
DESCRIPTION:F. Oort showed that the moduli space of principally polarized
supersingular abelian surfaces is a union of rational curves. This is prov
en by showing that every principally polarized supersingular abelian surf
ace is the Jacobian of a fibre of one of the families of genus 2 curves $
\\pi: \\mathcal{C}\\rightarrow \\mathbb{P}^1$ constructed by L. Moret-Bail
ly. We present an algorithm that makes this construction effective: Given
a point $x\\in \\mathbb{P}^1$ we compute a hyperelliptic model of the fib
re $\\pi^{-1}(x)$. The algorithm uses Mumford's theory of theta groups to
compute quotients by the group scheme $\\alpha_p$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Pieper Universität Ulm":MAILTO:
null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Pieper
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:284d93ab-1f80-4c1f-8f01-8e4224ef4a3b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220405T100000
SUMMARY:Towards computing the canonical lift of an ordinary elliptic curve
in medium characteristic
LOCATION:-
DESCRIPTION:Satoh's algorithm for counting the number of points of an elli
ptic curve $E/\\mathbb F_q$ with $q=p^n$ is the fastest known algorithm wh
en $p$ is fixed: it computes the invertible eigenvalue $»$ of the Frobeni
us to $p$-adic precision $m$ in time $\\tilde{O}(p^2 n m)$. Since by Hasse
's bound\, recovering $\\chi_{\\pi}$ requires working at precision $m=O(n)
$\, the point counting complexity is of $\\tilde{O}(p^2 n^2)$\, quasi-quad
ratic in the degree $n$.\nUnfortunately\, the term $p^2$ in the complexity
makes Satoh's algorithm suitable only for smaller $p$. For medium sized $
p$\, one can use Kedlaya's algorithm which cost $\\tilde{O}(p n^2 m)$ or a
variant by Harvey's which cost $\\tilde{O}(p^{1/2} n^{5/2} m + n^4 m)$\,
which have a better complexity on $p$ but a worse one on $n$. For large $p
$\, the SEA algorithm costs $\\tilde{O}(log^4 q)$.\nIn this talk\, we impr
ove the dependency on $p$ of Satoh's algorithm while retaining the depende
ncy on $n$ to bridge the gap towards medium characteristic. We develop a n
ew algorithm with a complexity of $\\tilde{O}(p n m)$. In the particular c
ase where we are furthermore provided with a rational point of $p$-torsion
\, we even improve this complexity to $\\tilde{O}(p^{1/2} n m)$.\nThis is
a joint work with Abdoulaye Maiga.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert IMB":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:4742338d-1841-44d5-b9e6-5d088297df83
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220412T100000
SUMMARY:A p-adic Descartes solver: the Strassman solve
LOCATION:-
DESCRIPTION:Solving polynomials is a fundamental computational problem in
mathematics. In the real setting\, we can use Descartes' rule of signs to
efficiently isolate the real roots of a square-free real polynomial. In th
is talk\, we show how to translate this method into the p-adic worlds. We
show how the p-adic analog of Descartes' rule of signs\, Strassman's theor
em\, leads to an algorithm to isolate the p-adic roots of a square-free p-
adic polynomial and provide some complexity estimates adapting the conditi
on-based complexity framework from real/complex numerical algebraic geomet
ry to the p-adic case.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Josué Tonelli-Cueto Inria Paris\, IMJ-
PRG":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Josué Tonelli-Cueto
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:29f10245-b2da-4266-a5f7-806fae9a8171
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220426T100000
SUMMARY:"Correspondance de Langlands inertielle explicite pour ${\nm GL}_2
$ et quelques applications arithmétiques"
LOCATION:-
DESCRIPTION:Dans cet exposé nous allons décrire une approche explicite q
ui permet de calculer les types automorphes inertiels pour ${\\rm GL}_2$.
Nous donnerons ensuite quelques applications de cet algorithme à des prob
lèmes diophantiens ou de nature arithmétique.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Lassina Dembélé King's College London"
:MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Lassina Dembélé
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:da543a48-3ca5-480a-8f3d-923cb366b93e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220503T100000
SUMMARY:The generating function of the Yang-Zagier Numbers is algebraic
LOCATION:-
DESCRIPTION:In a recent paper Don Zagier mentions a mysterious integer seq
uence $(a_n) _{n \\geq 0}$ which arises from a solution of a topological O
DE discovered by Marco Bertola\, Boris Dubrovin and Di Yang. In my talk I
show how to conjecture\, prove and even quantify that $(a_n) _{n \\geq 0}
$ actually admits an algebraic generating function which is therefore a ve
ry particular period. The methods are based on experimental mathematics an
d algorithmic ideas in differential Galois theory\, which I will show in t
he interactive part of the talk. The presentation is based on joint work w
ith A. Bostan and J.-A. Weil.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Sergey Yurkevich University of Vienna\,
Inria":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Sergey Yurkevich
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:40598c7f-073f-4b96-93e9-59c720c0a49e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220517T100000
SUMMARY:Résultats de type oméga pour les comptages de corps cubiques
LOCATION:-
DESCRIPTION:Il s'agit d'un travail en collaboration avec P. Cho\, Y. Lee e
t A. Södergren. Depuis les travaux de Davenport-Heilbronn\, beaucoup d'ar
ticles ont été ecrits donnant des estimations de plus en plus précises
sur le comptage du nombre de corps cubiques de discriminant au plus X. Men
tionnons par exemple les travaux de Belabas\, Belabas-Bhargava-Pomerance\,
Bhargava-Shankar-Tsimerman\, Taniguchi-Thorne et Bhargava-Taniguchi-Thorn
e. Dans cet exposé je parlerai d'un résultat négatif\, qui montre que l
'hypothèse de Riemann implique une limitation sur la plus petite taille p
ossible du terme d'erreur dans ces estimations. Nous approchons la questio
ns à partir de la théorie des petits zéros de fonctions $L$\, en partic
ulier la philosophie de Katz-Sarnak et les articles subséquents pour la f
amille des fonctions zeta de Dedekind de corps cubiques. Je présenterai a
ussi des résultats numériques obtenus avec pari/gp et le programme «cub
ic» de Belabas qui indiquent que notre résultat pourrait être optimal.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Daniel Fiorilli Université Paris Sacla
y":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Daniel Fiorilli
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:dd8075eb-2f52-461f-88a6-40f20c1acac6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220518T143000
SUMMARY:On the Lattice Isomorphism Problem\, Quadratic Forms\, Remarkable
Lattices\, and Cryptography
LOCATION:-
DESCRIPTION:A natural and recurring idea in the knapsack/lattice cryptogra
phy literature is to start from a lattice with remarkable decoding capabil
ity as your private key\, and hide it somehow to make a public key. This i
s also how the code-based encryption scheme of McEliece (1978) proceeds.\n
This idea has never worked out very well for lattices: ad-hoc approaches h
ave been proposed\, but they have been subject to ad-hoc attacks\, using t
ricks beyond lattice reduction algorithms. On the other hand the framework
offered by the Short Integer Solution (SIS) and Learning With Errors (LWE
) problems\, while convenient and well founded\, remains frustrating from
a coding perspective: the underlying decoding algorithms are rather trivia
l\, with poor decoding performance.\nIn this work\, we provide generic rea
lisations of this natural idea (independently of the chosen remarkable lat
tice) by basing cryptography on the Lattice Isomorphism Problem (LIP). Mor
e specifically\, we provide:\n- a worst-case to average-case reduction for
search-LIP and distinguish-LIP within an isomorphism class\, by extending
techniques of Haviv and Regev (SODA 2014).\n- a zero-knowledge proof of k
nowledge (ZKPoK) of an isomorphism. This implies an identification scheme
based on search-LIP.\n- a key encapsulation mechanism (KEM) scheme and a h
ash-then-sign signature scheme\, both based on distinguish-LIP.\nThe purpo
se of this approach is for remarkable lattices to improve the security and
performance of lattice-based cryptography. For example\, decoding within
poly-logarithmic factor from Minkowski's bound in a remarkable lattice wou
ld lead to a KEM resisting lattice attacks down to a poly-logarithmic appr
oximation factor\, provided that the dual lattice is also close to Minkows
ki's bound. Recent works have indeed reached such decoders for certain lat
tices (Chor-Rivest\, Barnes-Sloan)\, but these do not perfectly fit our ne
ed as their duals have poor minimal distance.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Wessel van Woerden CWI Amsterdam":MAILTO
:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Wessel van Woerden
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:9081e1a7-f62c-4dad-8ef5-d3a73f0fa607
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220524T100000
SUMMARY:Rigorous computation of class group and unit group
LOCATION:-
DESCRIPTION:Computing the class group and the unit group of a number field
is a famous problem of algorithmic number theory. Recently\, it has also
become an important problem in cryptography\, since it is used in multiple
algorithms related to algebraic lattices.\nSubexponential time algorithms
are known to solve this problem in any number fields\, but they heavily r
ely on heuristics. The only non-heuristic (but still under ERH) known algo
rithm\, due to Hafner and McCurley\, is restricted to imaginary quadratic
number fields.\nIn this talk\, we will see a rigorous subexponential time
algorithm computing units and class group (and more generally S-units) in
any number field\, assuming the extended Riemann hypothesis.\nThis is a jo
int work with Koen de Boer and Benjamin Wesolowski.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Alice Pellet-Mary CNRS/IMB":MAILTO:null
@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Alice Pellet-Mary
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:66dd66f7-e0c5-4348-9b3f-ef0c6cd74c2c
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220531T100000
SUMMARY:Sur quelques points\, plus ou moins effectifs\, de cohomologie des
groupes arithmétiques
LOCATION:-
DESCRIPTION:Nous donnerons un panorama de certaines techniques et résulta
ts pour le calcul de la cohomologie des groupes arithmétiques de rang $\\
ge 4$ pour des anneaux d'entiers algébriques\, ainsi que leurs applicatio
ns arithmétiques et K-théoriques. Nous ferons ensuite un focus sur les m
éthodes utilisant le modèle de Voronoi (euclidien ou hermitien)\, ainsi
que plusieurs améliorations algorithmiques. Nous préciserons certains r
ésultats relatifs aux complexes de Voronoi et leurs cellules (pour $\\mat
hrm{GL}_N$ avec $N \\geq 12$)\, ainsi qu'un travail en cours avec B. Allom
bert et R. Coulangeon sur les formes parfaites de rang $N$ sur $\\mathcal{
O}_K$ et la cohomologie de $\\mathrm{GL}_N(\\mathcal{O}_K)$ pour certains
anneaux d'entiers avec $N=4\,5\,6$. Nous mentionnerons aussi plusieurs pro
blèmes ouverts relatifs à ces modèles.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Philippe Elbaz-Vincent Institut Fourier
/ Inria / IMB":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Philippe Elbaz-Vincent
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:e1202837-a46b-4777-969c-fa841d23bb26
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220614T100000
SUMMARY:An explicit CRS-like action with Drinfeld modules
LOCATION:-
DESCRIPTION:L'une des pierres angulaires de la cryptographie des isogénie
s est l'action (dite CRS)\, simplement transitive\, du groupe des classes
d'un ordre d'un corps quadratique imaginaire\, sur un certain ensemble de
classes d'isomorphismes de courbes elliptiques ordinaires.\nL'échange de
clé non-interactif basé sur cette action (espace homogène difficile) es
t relativement lent (de Feo\, Kieffer\, Smith\, 2019) \; la structure du g
roupe (Beullens\, Kleinjung\, Vercauteren\, 2019) est difficile à calcule
r. Pour palier à cela\, nous décrivons une action\, simplement transitiv
e\, de la jacobienne d'une courbe hyperelliptique imaginaire\, sur un cert
ain ensemble de classes d'isomorphismes de modules de Drinfeld. \nAprès a
voir motivé l'utilisation des modules de Drinfeld en lieu et place des co
urbes elliptiques\, nous décrirons un algorithme efficace de calcul de l'
action\, ainsi que la récente attaque de Benjamin Wesolowski sur l'échan
ge de clé donné par l'action.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Antoine Leudière Université de Lorrain
e":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Antoine Leudière
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:32b19af5-275f-479b-80af-51fddbe19c79
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220628T100000
SUMMARY:Implementing fastECPP in CM
LOCATION:-
DESCRIPTION:FastECPP is currently the fastest approach to prove the primal
ity of general numbers\, and has the additional benefit of creating certif
icates that can be checked independently and with a lower complexity. It c
rucially relies on the explicit construction of elliptic curves with compl
ex multiplication.\nI will take you on a leisurely stroll through the diff
erent phases of the ECPP and fastECPP algorithms\, with explanations of th
eir complexity. We will then see the algorithmic choices I have made when
integrating a parallelised implementation of fastECPP into my CM software\, which has recently been
used to prove the primality of a number of record size 50000 digits<
/a>
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andreas Enge Inria/IMB":MAILTO:null@math
.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andreas Enge
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:696185b3-9780-4e51-834f-fbc4684dc7f7
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220712T100000
SUMMARY:Computing with polynomials over algebraic number fields
LOCATION:-
DESCRIPTION:Let $K = \\mathbb{Q}(\\alpha_1\,\\dots\,\\alpha_k)$ be an alge
braic number field. We are interested in computing polynomial GCDs in $K[x
]$ and $K[x_1\,\\dots\,x_n]$. Of course we also want to multiply\, divide
and factor polynomials over $K$. In $K[x]$ we have the Euclidean algorithm
but it "blows up"\; there is a growth in the size of the rational numbers
in the remainders. It is faster to compute the GCD modulo one or more pri
mes and use the Chinese remainder theorem and rational number reconstructi
on. This leads to computing a GCD in $R[x]$ where $R = K \\pmod p$ is usua
lly not be a field\; it is a finite ring.\nHow do Computer Algebra Systems
represent elements of $K$? How do Computer Algebra Systems compute GCDs i
n $K[x]$? What is the best way to do arithmetic in $R$? How can we compute
a polynomial GCD in $K[x_1\,\\dots\,x_n]$? In the talk we will try to ans
wer these questions and we will present some timing benchmarks comparing o
ur own C library for computing GCDs in $R[x]$ with Maple and Magma.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Michael Monagan Simon Fraser University"
:MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Michael Monagan
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:95f97801-d9b0-45ec-809a-7d242b18ba7a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220913T100000
SUMMARY:Breaking SIDH in polynomial time
LOCATION:-
DESCRIPTION:SIDH/SIKE was a post quantum key exchange mechanism based on i
sogenies between supersingular elliptic curves which was recently selected
in July 5 2022 by NIST to advance to the fourth round of the PQC competit
ion. It was soon after broken during the summer in a series of three paper
s by Castryck-Decru\, Maino-Martindale and myself.\nThe attacks all use th
e extra information on the torsion points used for the key exchange. We fi
rst review Petit's dimension 1 torsion point attack from 2017 which could
only apply to unbalanced parameters. Then we explain how the dimension 2 a
ttacks of Maino-Martindale and especially Castryck-Decru could break in heuristic (but in practice very effective) polynomial time some
parameters\, including the NIST submission where the starting curve
$E: y^2=x^3+x$ has explicit endomorphism $i$.\nFinally we explain how by g
oing to dimension 8\, we could break in proven quasi-linear time
all parameters for SIKE.\nWe will explain how the SIDH protocol w
orked at the beginning of the talk. We will see that the attack ultimately
relies on a very simple 2x2 matrix computation! There will also be (hopef
ully) fun memes during the talk!
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert Inria/IMB":MAILTO:null@ma
th.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:0977be85-31e2-4445-9e96-a751ed725ca9
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20220920T100000
SUMMARY:Faster computation of elementary functions
LOCATION:-
DESCRIPTION:Over a decade ago\, Arnold Schönhage proposed a method to com
pute elementary functions (exp\, log\, sin\, arctan\, etc.) efficiently in
"medium precision" (up to about 1000 digits) by reducing the argument usi
ng linear combinations of pairs of logarithms of primes or Gaussian primes
. We generalize this approach to an arbitrary number of primes (which in p
ractice may be 10-20 or more)\, using an efficient algorithm to solve the
associated Diophantine approximation problem. Although theoretically slowe
r than the arithmetic-geometric mean (AGM) by a logarithmic factor\, this
is now the fastest algorithm in practice to compute elementary functions f
rom about 1000 digits up to millions of digits\, giving roughly a factor-t
wo speedup over previous methods. We also discuss the use of optimized Mac
hin-like formulas for simultaneous computation of several logarithms or ar
ctangents of rational numbers\, which is required for precomputations.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Fredrik Johansson Inria/IMB":MAILTO:nul
l@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Fredrik Johansson
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:5d3ce761-239d-4b3f-aa3c-6b5a50e1b3dd
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20221004T100000
SUMMARY:Présentation des nouveaux doctorants de l'équipe LFANT
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pierrick Dartois\, Fabrice Etienne et Ni
colas Sarkis null":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pierrick Dartois\, Fabrice Etienne et Nicolas Sarkis
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:879f66d2-a16e-480c-99e7-b18ae07c72c4
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20221011T100000
SUMMARY:Computation of (3\,3)-isogenies from a product of elliptic curves\
, in the style of 19th century geometry
LOCATION:-
DESCRIPTION:The method found by W. Castryck and T. Decru to break SIDH req
uires computing $(2^n\,2^n)$-isogenies from a product of elliptic curves t
o another abelian surface (which is also a product)\, which are realized a
s degree 2 correspondences between curves.\nTransposing the attack to the
other side of the SIDH exchange involves degree $(3\,3)$-isogenies that ca
n be evaluated using either theta functions\, or divisors on genus 2 curve
s. Methods for the curve approach exist for the Jacobian case\, but the c
ase of a product of elliptic curves (Bröker\, Howe\, Lauter\, Stevenhagen
2014) can be difficult to implement for cryptographically relevant field
sizes due to various limitations in CAS such as SageMath/Singular.\nI will
explain how traditional algebraic geometry can be called to the rescue to
give a simple construction of the curve correspondence associated to the
quotient of $E_1 \\times E_2$ by an isotropic $(3\,3)$-kernel. This leads
to a rather fast computation method relying only on elementary field opera
tions and 2 square roots. The journey will bring back some memories of 19
th century projective geometry. Theta function experts might recognize fam
iliar objects in the geometric construction.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Rémy Oudompheng -":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Rémy Oudompheng
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:de27895f-d4ea-468c-988b-2e74cc2a6757
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20221018T100000
SUMMARY:Some Easy Instances of Ideal-SVP and Implications on the Partial V
andermonde Knapsack Problem
LOCATION:-
DESCRIPTION:In our article\, we generalize the works of Pan et al. (Eurocr
ypt 21) and Porter et al. (ArXiv 21) and provide a simple condition under
which an ideal lattice defines an easy instance of the shortest vector pro
blem. Namely\, we show that the more automorphisms stabilize the ideal\, t
he easier it is to find a short vector in it. This observation was already
made for prime ideals in Galois fields\, and we generalize it to any idea
l (whose prime factors are not ramified) of any number field. We then prov
ide a cryptographic application of this result by showing that particular
instances of the partial Vandermonde knapsack problem\, also known as part
ial Fourier recovery problem\, can be solved classically in polynomial tim
e.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Èrell Gachon -":MAILTO:null@math.u-bord
eaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Èrell Gachon
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:22ed8b86-9083-44ad-b2db-8e2dcce33e99
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20221025T000000
SUMMARY:Evaluating isogenies in polylogarithmic time
LOCATION:-
DESCRIPTION:We explain how the « embedding lemma » used in the recents
attacks against SIDH can be used constructively. Namely we show that ever
y $N$-isogeny between abelian varieties over a finite field admits an effi
cient representation allowing for its evaluation in time polylogarithmic i
n $N$. Furthermore\, using Vélu's formula for elliptic curves\, or isogen
ies in the theta model for dimension $g>\;1$\, this representation can b
e computed in time quasi-linear in $N^g$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Damien Robert Inria/IMB":MAILTO:null@ma
th.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Damien Robert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:aa916619-ecc5-467a-abf9-7f9a1c9a0c26
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20221108T100000
SUMMARY:Énumération des corps de nombres quartiques
LOCATION:-
DESCRIPTION:Fixons un entier $n \\geq 2$\, et\, pour $X \\geq 0$\, soit $C
_n(X)$ l'ensemble des classes d'isomorphisme de corps de nombres de degré
$n$ et de discriminant inférieur à $X$ en valeur absolue. La méthode d
e Hunter-Pohst permet d'énumérer $C_n(X)$ en temps $O(X^{\\frac{n + 2}{
4} + epsilon})$. Pour $n \\geq 3$\, on s'attend à ce que cette complexit
é ne soit pas optimale : en effet\, une conjecture classique\, démontré
e pour $n leq 5$\, prévoit qu'il existe une constante $c_n \\geq 0$ tell
e que le cardinal de $C_n(X)$ soit équivalent à $c_n X$. En utilisant un
e paramétrisation des corps cubiques due à Davenport et Heilbronn\, Bela
bas a mis au point un algorithme énumérant $C_3(X)$ en temps optimal $O(
X^{1 + \\epsilon})$. Je montrerai comment une paramétrisation des corps q
uartiques due à Bhargava permet de manière similaire d'énumérer $C_4(X
)$ en temps $O(X^{\\frac{5}{4} + \\epsilon})$. Je présenterai ensuite des
résultats numériques\, ainsi que des perspectives d'amélioration et de
généralisation en degré supérieur.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Anne-Edgar Wilke IMB":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Anne-Edgar Wilke
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:2990c968-130e-4096-a416-0388014a6b5a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20221115T100000
SUMMARY:A Pari/GP package for continued fractions
LOCATION:-
DESCRIPTION:I will describe with numerous examples a new Pari/GP package f
or infinite continued fractions which can in particular compute numericall
y the limit\, the exact asymptotic speed of convergence (almost never give
n in the literature)\, accelerate continued fractions\, and especially app
ly the powerful Apéry acceleration technique to almost all continued frac
tions\, leading to hundreds of new ones.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henri Cohen IMB":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henri Cohen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:59adbba0-eeb3-4d34-b78b-bbfce2e5036a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20221122T100000
SUMMARY:Index calculus attacks on hyperelliptic curves with efficient endo
morphism
LOCATION:-
DESCRIPTION:The security of many existing cryptographic systems relies on
the difficulty of solving the discrete logarithm problem (DLP) in a group
. For a generic group\, we can solve this problem with many algorithms su
ch as the baby-step-giant-step\, the Pollard-rho or the Pohlig-Hellman a
lgorithm. For a group with known structure\, we use the index calculus al
gorithm to solve the discrete logarithm problem. Then\, the DLP on the Ja
cobian of a hyperelliptic curve defined over a finite field $\\mathbb{F}_
{q^n}$ with $n >1$ are subject to index calculus attacks. After having c
hosen a convenient factor basis\, the index calculus algorithm has three
steps - the decomposition step in which we decompose a random point in t
he factor basis\, the linear algebra step where we solve a matricial equ
ation and the descent phase in which the discrete logarithm is deduced. T
he complexity of the algorithm crucially depends on the size of the fact
or basis\, since this determines the probability for a point to be decomp
osed over the base and also the cost of the linear algebra step. Faugèr
e et al (EC 2014) exploit the $2$-torsion point of the curve to reduce t
he size of the factor basis and then improve the complexity of the index
calculus algorithm. In a similar manner\, we exploit the endomorphism of
the Jacobian to reduce the size of the factor base for certain families o
f ordinary elliptic curves and genus $2$ hyperelliptic Jacobians defined
over finite fields. This approach adds an extra cost when performing oper
ation on the factor basis\, but our benchmarks show that reducing the siz
e of the factor base allows to have a gain on the total complexity of ind
ex calculus algorithm with respect to the generic attacks.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Sulamithe Tsakou -":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Sulamithe Tsakou
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:88c907cd-2e80-46ac-af8e-c6a1a2a3408f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20221129T100000
SUMMARY:Searching substrings inside an encrypted stream of data ... withou
t decrypting !
LOCATION:-
DESCRIPTION:Outsourcing IT services has become very common worldwide for m
ultiple reasons ranging from costs reduction to improved services. Whateve
r the actual reason is\, the concrete consequence for the company that de
legates such services is that a third party ends up with its data in clea
r because of the well-known limitations of standard encryption.\nIdeally\
, this third party should only learn the minimal information necessary fo
r performing the requested processing\, which has motivated the design of
countless encryption schemes compatible with specific processing. Such s
chemes belong to the realm of functional encryption\, where the third par
ty recovers a function f(x) from an encryption of x without learning anyt
hing else about x\, with minimal interaction. Of course\, the function f\
, and hence the encryption scheme\, strongly depends on the considered ap
plication\, which explains the profusion of papers related to this topic.
We will focus on the possibility to allow a third party to search the pr
esence of chosen substrings of different lengths (and more !) at any posi
tion in the encryption of a stream of data. After an introduction to this
problematic and to the associated security notion\, we will take a look
at the proof of security of one specific construction.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Elie Bouscatié -":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Elie Bouscatié
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:258104f8-c914-4006-bf72-5acb495ba528
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20221206T100000
SUMMARY:Admissibility of filtered $(\\varphi\,N)$-modules
LOCATION:-
DESCRIPTION:Filtered $(\\varphi\,N)$-modules over a $p$-adic field $K$ are
semi-linear objects which are easy to define and can be implemented on a
computer. The modules $D_{st}(V)$ defined by $p$-adic Hodge theory\, wher
e $V$ is a $p$-adic representation of the absolute Galois group of $K$\,
provide examples of filtered $(varphi\,N)$-modules. When $V$ is nice enou
gh (semi-stable)\, the data of $D_{st}(V)$ is sufficient to recover $V$.
A necessary and sufficient condition for a filtered $(\\varphi\,N)$-modul
e $D$ to be written as $D_{st}(V)$ for some semi-stable representation $V
$ is the condition of "admissibility" which imposes conditions on the way
the different structures of the $(varphi\,N)$-module interact with each
other.\nIn a joint work with Xavier Caruso\, we try to provide an algorith
m which takes a filtered $(\\varphi\,N)$-module as an input and outputs w
hether it is admissible or not. I will explain how we can implement filte
red $(\\varphi\,N)$-modules on a computer and why this question is well p
osed. I will then present an algorithm which answers the question if the
$(\\varphi\,N)$-module is nice enough and explain the difficulties we are
facing both in this nice case and in the general case.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Léo Poyeton -":MAILTO:null@math.u-borde
aux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Léo Poyeton
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:aa8f3a4f-1144-487b-ac8b-2ac32ba781ce
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20221213T100000
SUMMARY:Points de torsion d'une variété abélienne dans des extensions d
'un corps fixé
LOCATION:-
DESCRIPTION:Pour une variété abélienne A sur un corps de nombres K\, on
sait que pour toute extension finie L/K\, le nombre c(L) de points de tor
sion de A(L) est fini par le théorème de Mordell-Weil.
En fait\,
un résultat de Masser prédit que c(L) est polynomial en [L:K] (si on fix
e A et K) avec un exposant g=dim A\, et une conjecture de Hindry et Rata
zzi de 2012 donne l'exposant optimal (plus petit que g en général) en f
onction d'une certaine structure de la variété abélienne (liée à son
groupe dit de Mumford-Tate)\nDans cet exposé\, je parlerai d'un travail
commun avec Lombardo et Zywina dans lequel nous démontrons une forme inc
onditionnelle de cette conjecture (et cette conjecture en admettant la co
njecture de Mumford-Tate)\, en insistant sur les résultats intermédiair
es qui peuvent être d'intérêt indépendant pour la compréhension des
représentations galoisiennes associées à des variétés abéliennes.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Samuel Le Fourn -":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Samuel Le Fourn
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1f60403f-32df-4aca-9aea-b1749fca4017
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230117T100000
SUMMARY:Radical isogeny formulas
LOCATION:-
DESCRIPTION:In several applications one is interested in a fast computatio
n of the codomain curve of a long chain of cyclic $N$-isogenies emanating
from an elliptic curve E over a finite field $\\mathbb F_q$\, where $N = 2
\, 3\, \\ldots$ is some small fixed integer coprime to $q$. The standard
approach proceeds by finding a generator of the kernel of the first $N$-is
ogeny\, computing its codomain via Vélu's formulas\, then finding a gener
ator of the kernel of the second $N$-isogeny\, and so on. Finding these ke
rnel generators is often the main bottleneck.\nIn this talk I will explain
a new approach to this problem\, which was studied in joint work with Tho
mas Decru\, Marc Houben and Frederik Vercauteren. We argue that Vélu's fo
rmulas can be augmented with explicit formulas for the coordinates of a ge
nerator of the kernel of an $N$-isogeny cyclically extending the previous
isogeny. These formulas involve the extraction of an $N$-th root\, therefo
re we call them "radical isogeny formulas". By varying which $N$-th root w
as chosen (i.e.\, by scaling the radical with different $N$-th roots of un
ity) one obtains the kernels of all possible such extensions. Asymptotical
ly\, in our main cases of interest this gives a speed-up by a factor 6 or
7 over previous methods.\nI will explain the existence of radical isogeny
formulas\, discuss methods to find them (the formulas become increasingly
complicated for larger N)\, and pose some open questions.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Wouter Castryck -":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Wouter Castryck
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:2aa6775a-fe62-4373-b990-bf381c3913ae
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230124T100000
SUMMARY:The particular case of cyclotomic fields whencomputing unit groups
by quantum algorithms
LOCATION:-
DESCRIPTION:The computation of unit and class groups in arbitrary degree n
umber field is done in polynomial time in a similar fashion to the Shor's
factoring algorithm. Contrary to the fixed degree case which was solved i
n 2001 by Hallgren and a follow-up paper of Schmidt and Vollmer (2005)\, t
he arbitrary degree case requires errors estimations and is solved by the
conjunction of two papers\, Eisenträger et al. (2014) and de Boer et a
l. (2020).\nIn the particular case of cyclotomic fields we propose a versi
on of the algorithm which makes use of cyclotomic units. Indeed\, the Sho
r-like procedure of Eisenträger et al.'s algorithm produces random appro
ximations of vectors in the dual of the lattice of units. In order to gua
rantee the correction of the algorithm\, they have to do the computations
in high precision and hence require a large amount of qubits. Thanks to
the lattice of cyclotomic units\, one can do the computations in smaller
precision and reduce the number of qubits.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Razvan Barbulescu CNRS/IMB":MAILTO:null
@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Razvan Barbulescu
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:82a6cd8e-58d7-46d8-a242-26a8f1618034
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230131T100000
SUMMARY:An Algorithmic Reduction Theory for Binary Codes\, LLL and more
LOCATION:-
DESCRIPTION:We will discuss an adaptation of the algorithmic reduction the
ory of lattices to binary codes. This includes the celebrated LLL algorit
hm (Lenstra\, Lenstra\, Lovasz\, 1982)\, as well as adaptations of associ
ated algorithms such as the Nearest Plane Algorithm of Babai (1986). Inte
restingly\, the adaptation of LLL to binary codes can be interpreted as a
n algorithmic version of the bound of Griesmer (1960) on the minimal dis
tance of a code.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Wessel van Woerden IMB":MAILTO:null@math
.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Wessel van Woerden
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a290c246-b38c-43ba-ac3d-5d5458615936
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230207T100000
SUMMARY:Calcul de racines de polynômes dans un corps de nombres
LOCATION:-
DESCRIPTION:Computing roots of elements is an important step when solving
various tasks in computational number theory. It arises for example durin
g the final step of the General Number Field Sieve~(Lenstra et al. 1993).
This problem also intervenes during saturation processes while computing
the class group or $S$-units of a number field (Biasse and Fieker). \nI
t is known from the seminal paper introducing the LLL algorithm that one
can recover elements of a given number field $K$ given approximations of
one of their complex embeddings. This can be used to compute roots of pol
ynomials. In the first part of this presentation\, I will describe an ext
ension of this approach that take advantage of a potential subfield $k$\,
which replace the decoding of one element of $K$ by the decoding $[K:k]$
elements of $k$\, to the cost of search in a set of cardinality $d^{[K:k
]}$ where $d$ is the degree of the targetted polynomial equation. We will
also describe heuristic observations that are useful to speed-up computa
tions.\nIn the second part of the presentation\, we will describe methods
to compute $e$-th roots specifically. When $K$ and $e$ are such that the
re are infinitely many prime integers $p$ such that $\\forall mathfrak{p}
\\mid p\, p^{f(\\mathfrak{p}\\mid p)} \\not equiv1 \\pmod e$\, we recons
truct $x$ from $x \\pmod {p_1}\, dots\, x \\pmod {p_r} $ using a generali
sation of Thomé's work on square-roots in the context of the NFS~(Thomé
). When this good condition on $K$ and $n$ is not satisfied\, one can ada
pt Couveignes' approach for square roots (Couveignes) to relative extensio
ns of number fields $K/k$ provided $[K:k]$ is coprime to $e$ and infinite
ly many prime integers $p$ are such that each prime ideal $\\mathfrak{p}$
of $\\mathcal{O}_k$ above $p$ is inert in $K$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Andrea Lesavourey Irisa":MAILTO:null@mat
h.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Andrea Lesavourey
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6b7b5f77-9166-4d4a-8257-34fc3440d94d
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230214T100000
SUMMARY:Exploiting algebraic structure in probing security
LOCATION:-
DESCRIPTION:The so-called $\\omega$-encoding\, introduced by Goudarzi\, Jo
ux and Rivain (Asiacrypt 2018)\, generalizes the commonly used arithmetic
encoding. By using the additionnal structure of this encoding\, they pro
posed a masked multiplication gadget (GJR) with quasilinear (randomness a
nd operations) complexity. A second contribution by Goudarzi\, Prest\, Ri
vain and Vergnaud in this line of research appeared in TCHES 2021. The au
thors revisited the aforementioned multiplication gadget (GPRV)\, and bro
ught the IOS security notion for refresh gadgets to allow secure composit
ion between probing secure gadgets.\nIn this paper\, we propose a follow
up on GPRV. Our contribution stems from a single Lemma\, linking algebra
and probing security for a wide class of circuits\, further exploiting th
e algebraic structure of $\\omega$-encoding. On the theoretical side\, we
weaken the IOS notion into the KIOS notion\, and we weaken the usual $t$
-probing security into the RTIK security. The composition Theorem that we
obtain by plugging together KIOS\, RTIK still achieves region-probing se
curity for composition of circuits.\nTo substantiate our weaker definition
s\, we also provide examples of competitively efficient gadgets verifying
our weaker security notions. Explicitly\, we give 1) a refresh gadget th
at uses $d-1$ random field elements to refresh a length $d$ encoding that
is KIOS but not IOS\, and 2) multiplication gadgets asymptotically subqu
adratic in both randomness and complexity. While our algorithms outperfor
m the ISW masked compiler asymptotically\, their security proofs require
a bounded number of shares for a fixed base field.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Maxime Plançon IBM Zürich":MAILTO:null
@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Maxime Plançon
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1ffb659a-5f74-4356-be44-c18b2e3973bf
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230221T100000
SUMMARY:Arithmetic equivalence and successive minima
LOCATION:-
DESCRIPTION:Two number fields are said to be arithmetically equivalent if
they have the same Dedekind zeta function. The central question about ari
thmetic equivalence is to determine how "similar" arithmetically equivale
nt number fields are. That is\, we would like to determine which arithmet
ic invariants\, such as the degree\, discriminant\, signature\, units\, cl
ass number\, etc.\, are the same\, and which ones can differ. A key resul
t about arithmetic equivalence is Gassmann's theorem\, which allows one t
o answer such questions using Galois theory and representation theory.\nI
will give a general introduction to arithmetic equivalence\, discussing
some of the main results such as Gassmann's theorem and giving examples.
I will then introduce the successive minima of a number field\, and show
that arithmetically equivalent number fields have approximately the same
successive minima.\n "
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Floris Vermeulen KU Leuven":MAILTO:null@
math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Floris Vermeulen
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:846118c7-e531-4b7c-bcb5-e58a5d923cf6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230308T100000
SUMMARY:Elliptic Curves over Galois Number Fields
LOCATION:-
DESCRIPTION:As E varies among elliptic curves defined over the rational nu
mbers\, a theorem of Bhargava and Shankar shows that the average rank of
the Mordell-Weil group $E(\\mathbb Q)$ is bounded. If we now fix a Galoi
s number field K\, how does the Mordell-Weil group E(K) behave on average
as a Galois module? We will report on progress on this question\, which
is obtained by instead studying the associated p-Selmer groups of E/K as
Galois modules.\nWe construct some novel Selmer groups which describe cert
ain invariants of these modules\, and go on to study the behaviour of the
se new Selmer groups. This in turn allows us to give bounds for certain be
haviour for the Mordell-Weil groups.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Ross Paterson University of Bristol":MAI
LTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Ross Paterson
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:33726930-1b5d-4b68-a289-e6d0a33130b3
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230314T100000
SUMMARY:Oriented Supersingular Elliptic Curves and Class Group Actions
LOCATION:-
DESCRIPTION:We recently defined an OSIDH protocol with Kohel (OSIDH) for o
riented supersingular isogeny Diffie-Hellman by imposing the data of an
orientation by an imaginary quadratic ring $\\mathcal{O}$ on the category
of supersingular elliptic curves. Starting with an elliptic curve $E_0$
oriented by a CM order $\\mathcal{O}_K$ of class number one\, we push forw
ard the class group action along an $\\ell$-isogeny chains\, on which the
class group of an order $\\mathcal{O}$ of large index $\\ell^n$ in $\\mat
hcal{O}_K$ acts. The map from $\\ell$-isogeny chains to its terminus forg
ets the structure of the orientation\, and the original base curve $E_0$.
For a sufficiently long random $ell$-isogeny chain\, the terminal curve
represents a generic supersingular elliptic curve.\nOne of the advantages
of working in this general framework is that the group action by $\\math
rm{Cl}(\\mathcal{O})$ can be carried out effectively solely on the sequen
ce of moduli points (such as $j$-invariants) on a modular curve\, thereby
avoiding expensive generic isogeny computations or the requirement of ra
tional torsion points.\nThe proposed attacks of Onuki (2021) and Dartois-D
e Feo (2021) and their analyses motivate the idea of enlarging the class
group without touching the key space using clouds. In this talk we
propose two approaches to augment $\\mathrm{Cl}(\\mathcal{O}_n(M))$ in a
way that no effective data is transmitted for a third party to compute c
ycle relations. In both cases\, it comes down to an extension of the init
ial chain by the two parties separately. In particular\, while the origin
al OSIDH protocol made exclusive use of the class group action at split p
rimes in $\\mathcal{O}$\, we extend the protocol to include descent in th
e eddies at non-split primes (inert or ramified) or at large primes which
are not cost-effective for use for longer isogeny walks.\n "
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Leonardo Colô Université Aix-Marseill
e":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Leonardo Colô
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:0e8fb8f1-27bb-4aa9-9b02-0d8ba12bcfaa
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230321T100000
SUMMARY:High dimensional computation of fundamental domains
LOCATION:-
DESCRIPTION:We have developed open-source software in C++ for computing wi
th polyhedra\, lattices\, and related algebraic structures. We will shortl
y explain its design. Then we will explain how it was used for computing t
he dual structure of the $W(H_4)$ polytope.\nThen we will consider another
application to finding the fundamental domain of cocompact subgroups $G$
of $\\mathrm{SL}_n(\\mathbb{R})$. The approach defines a cone associated
with the group and a point $x\\in \\mathbb{R}^n$. It is a generalization
of Venkov reduction theory for $\\mathrm{GL}_n(\\mathbb{Z})$. We recall t
he Poincaré Polyhedron Theorem which underlies these constructions.\nWe g
ive an iterative algorithm that allows computing a fundamental domain. The
algorithm is based on linear programming\, the Shortest Group Element (SG
E) problem and combinatorics. We apply it to the Witte cocompact subgroup
of $\\mathrm{SL}_3(\\mathbb{R})$ defined by Witte for the cubic ring of d
iscriminant $49$.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Mathieu Dutour Institute Rudjer Boskovic
\, Croatia":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Mathieu Dutour
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:3ac8a892-aa66-41de-a273-2b2896ccaf26
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230328T100000
SUMMARY:Hull attacks on the Lattice Isomorphism Problem
LOCATION:-
DESCRIPTION:The lattice isomorphism problem (LIP) asks one to find an isom
etry between two lattices. It has recently been proposed as a foundation
for cryptography in independent works. This problem is the lattice varian
t of the code equivalence problem\, on which the notion of the hull of a
code can lead to devastating attacks. In this talk I will present the cry
ptanalytic role of an adaptation of the hull to the lattice setting\, whi
ch we call the s-hull. Specifically\, we show that the hull can be helpfu
l for geometric attacks\, for certain lattices the minimal distance of th
e hull is relatively smaller than that of the original lattice\, and this
can be exploited. The attack cost remains exponential\, but the constant
in the exponent is halved.
Our results suggests that one should be
very considerate about the geometry of hulls when instantiating LIP for
cryptography. They also point to unimodular lattices as attractive option
s\, as they are equal to their own hulls. Remarkably\, this is already th
e case in proposed instantiations\, namely the trivial lattice $\\mathbb{
Z}^n$ and the Barnes-Wall lattices.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Shane Gibbons CWI\, Netherlands":MAILTO
:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Shane Gibbons
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:cb140f34-03ad-4d59-bdd6-a6c68f9d7f8c
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230404T100000
SUMMARY:Finite subgroups of $mathrm{PGL}_2(mathbb{Q})$ and number fields w
ith large class groups
LOCATION:-
DESCRIPTION:For each finite subgroup $G$ of $\\mathrm{PGL}_2(\\mathbb{Q})$
\, and for each integer $n$ coprime to $6$\, we construct explicitly infin
itely many Galois extensions of $\\mathbb{Q}$ with group $G$ and whose ide
al class group has $n$-rank at least $#G-1$. This gives new $n$-rank recor
ds for class groups of number fields.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean Gillibert Université de Toulouse 2
":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean Gillibert
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c59f47e5-2af9-4613-9e79-df4a55764c6d
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230411T100000
SUMMARY:An inverse problem for isogeny volcanoes
LOCATION:-
DESCRIPTION:Supersingular isogeny graphs are very complicated and intricat
e\, and are used extensively by cryptographers. On the other side of thin
gs\, the structure of ordinary isogeny graphs is well understood connecte
d components look like volcanoes. Throughout this talk we will explore th
e ordinary $\\ell$-isogeny graph over $\\mathbb{F}_p$ for various prime n
umbers $\\ell$ and $p$\, and answer the following question\, given a volc
ano-shaped graph\, can we always find an isogeny graph in which our volca
no lives as a connected component?
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Henry Bambury ENS Ulm":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Henry Bambury
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6f543d49-ae1b-4bf7-98b6-4ff87fd329bc
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230425T100000
SUMMARY:Computing $L'(1\,chi)/L(1\,chi)$ using special functions\, their r
eflection formulae and the Fast Fourier Transform
LOCATION:online
DESCRIPTION:We will show how to combine the Fast Fourier Transform algorit
hm with the reflection formulae of the special functions involved in the
computation of the values of $L(1\,chi)$ and $L'(1\,chi)$\, where $chi$ r
uns over the Dirichlet characters modulo an odd prime number $q$. In this
way\, we will be able to reduce the memory requirements and to improve t
he computational cost of the whole procedure. \nSeveral applications to n
umber-theoretic problems will be mentioned\, like the study of the distri
bution of the Euler-Kronecker constants for the cyclotomic field and its
subfields\, the behaviour of $min_{chie chi_0} | L'(1\,chi)/L(1\,chi) |$\
, the study of the Kummer ratio for the first factor of the class number
of the cyclotomic field and the ``Landau vs. Ramanujan`` problem for divi
sor sums and coefficients of cusp forms. Towards the end of the seminar w
e will tackle open problems both of theoretical and implementative nature
.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Alessandro Languasco University of Padov
a\, Italy":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Alessandro Languasco
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:2cc4fce7-24db-4617-8e85-691e2b87e6a7
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230502T100000
SUMMARY:Computing bad reduction for genus 3 curves with complex multiplica
tion
LOCATION:salle 2
DESCRIPTION:Goren and Lauter studied genus 2 curves whose Jacobians are ab
solutely simple and have complex multiplication (CM) by the ring of integ
ers of a quartic CM-field\, and showed that if such a curve has bad reduc
tion to characteristic p then there is a solution to a certain embedding
problem. An analogous formulation of the embedding problem for genus 3 d
oes not suffice for explicitly computing all primes of bad reduction. We
introduce a new problem called the Isogenous Embedding Problem (IEP)\, wh
ich we relate to the existence of primes of bad reduction. We propose an
algorithm which computes effective solutions for this problem and exhibit
s a list of primes of bad reduction for genus 3 curves with CM. We ran th
is algorithm through different families of curves and were able to prove
the reduction type of some particular curves at certain primes that were
open cases in the literature.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Sorina Ionica Université de Picardie":
MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Sorina Ionica
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1ec180d6-f50f-4289-88d9-a3baa3553e9b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230509T100000
SUMMARY:Isogeny-based PAKE protocols
LOCATION:salle 2
DESCRIPTION:The passwords that we use in our everyday life are often chose
n to be easily memorable which evidently makes them vulnerable to attacks
. This problem is addressed by password-authenticated key exchange (PAKE)
. The general idea of such a protocol is to enable two parties who share
the same (potentially weak) password to establish a strong session key. M
ost PAKE protocols used today are based on Diffie-Hellman key exchange in
prime order groups\, hence they are not secure against quantum attackers.
A promising candidate for replacing Diffie-Hellman key exchange in a pos
t-quantum world is the Commutative-Supersingular-Isogeny-Diffie-Hellman (
CSIDH) key exchange. In this talk\, we introduce two novel PAKE protocols
based on CSIDH.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Sabrina Kunzweiler IMB":MAILTO:null@math
.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Sabrina Kunzweiler
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:83fcfdf5-bce0-43b6-92ac-f5bdce9594b9
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230516T100000
SUMMARY:Perfect Quadratic Forms -- an Upper Bound and Challenges in Enumer
ation
LOCATION:salle 2
DESCRIPTION: In 1908 Voronoi introduced an algorithm that solves the\n
lattice packing problem in any dimension in finite time. Voronoi showed\
n that any lattice with optimal packing density must correspond to a so
-\n called perfect (quadratic) form and his algorithm enumerates the\n
finitely many perfect forms up to similarity in a fixed dimension.\n
However\, the number of non-similar perfect forms and the comlexity of\n
the algorithm grows quickly in the dimension and as a result Voronoi’
s\n algorithm has only been completely executed up to dimension 8. We\n
discuss an upper bound on the number of perfect forms and the\n cha
llenges that arise for completing Voronoi's algorithm in dimension 9.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Wessel van Woerden IMB":MAILTO:null@math
.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Wessel van Woerden
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:1526245c-c6dd-4a9b-a171-5927b5318852
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230523T100000
DTEND;TZID=Europe/Paris:20230523T110000
SUMMARY:Beyond the SIDH Countermeasures
LOCATION:bâtiment Inria\, salle Sophie Germain (304)
DESCRIPTION: During summer 2022\, a series of three cryptanalysis paper
s lead to a
polynomial time attack on SIKE\, which was in the fourt
h round of the NIST
standardisation process. In a recent work\, we
explored countermeasures
avenue to the SIDH attacks\, M-SIDH and MD
-SIDH.
These countermeasures\, despite being slow and less compact
(when compared
to SIDH and other post-quantum schemes)\, come with
new insights that may be
of independent interest. In this talk\, w
e will discuss an on-going work in
which we use M-SIDH together wit
h the SIDH attacks to design a trapdoor one
way function. This trap
door one way function can be leveraged to obtain a
public key encry
ption scheme\, most importantly\, it can be used to design an
Ident
ity Based Encryption scheme. The main drawback is that the design is
purely theoretical at the moment\, since inverting the one way function
requires computing isogenies in higher dimension of prime degree
up to
5000 or even higher.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Boris Fuoutsa EPFL\, Switzerland":MAILTO
:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Boris Fuoutsa
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:99ce5c69-9bcd-4784-a6ca-7a78b1b21dba
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230530T100000
SUMMARY:Adding Level Structure to Supersingular Elliptic Curve Isogeny Gra
phs
LOCATION:salle 2
DESCRIPTION:The classical Deuring correspondence provides a roadmap betwee
n supersingular elliptic curves and the maximal orders which are isomorph
ic to their endomorphism rings. Building on this idea\, we add the inform
ation of a cyclic subgroup of prime order N to supersingular elliptic cur
ves\, and prove a generalisation of the Deuring correspondence for these
objects. We also study the resulting ell-isogeny graphs supersingular elli
ptic curve with level-N structure\, and the corresponding graphs in the re
alm of quaternion algebras. The structure of the supersingular elliptic c
urve ell-isogeny graph underlies the security of a new zero-knowledge pro
of of isogeny knowledge.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Sarah Arpin University of Leiden\, Nethe
rlands":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Sarah Arpin
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:183084b6-84ca-488a-9be5-0661b4e794ff
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230606T100000
SUMMARY:The Closest Vector Problem for the lattice of algebraic integers
LOCATION:salle 2
DESCRIPTION:Any number field comes with a natural inner product as in the
theory of the geometry of numbers\, so that any order becomes a lattice.We extend the definition of the inner product to $\\overline{\\mathbb{Q}
}$\, the algebraic closure of the rationals\, and consider its maximal ord
er $\\overline{\\mathbb{Z}}$\, which has infinite rank\, as an intrinsical
ly interesting `lattice'.
We will compute several lattice invariants an
d attempt to solve the Closest Vector Problem through proofs inspired by c
apacity theory.
Adjacent to CVP is the problem of finding the Voronoi-r
elevant vectors\, and we pose the challenge to compute all such vectors of
degree 3.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Daan van Gent (University of Leinden\, N
etherlands":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Daan van Gent
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a94ba421-155c-4f2d-b78b-ded747210031
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230613T100000
SUMMARY:Constrained Pseudorandom Functions from Homomorphic Secret Sharing
LOCATION:salle 2
DESCRIPTION: A Constrained pseudorandom function (CPRF) is a pseudorand
om function that\n provides fine-grained access to the evaluation of th
e function. In other\n words\, for a (possibly super-polynomial) subset
of inputs\, a constrained\n pseudorandom function allows us to derive
a constrained key that enables\n evaluating the function on that subset
of inputs while learning nothing\n beyond. We propose and analyze a si
mple strategy for constructing 1-key\n constrained pseudorandom functio
ns from homomorphic secret sharing (HSS)\n protocols. This relation\, i
n particular\, leads to instantiations of CPRFs\n for various constrain
ts and from various assumptions. In this talk\, I\n present this strate
gy and briefly go over one of the instantiations.\n
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Mahshid Riahinia ENS de Lyon":MAILTO:nu
ll@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Mahshid Riahinia
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c5d732a7-d9ef-4436-8e90-abc61bb3db60
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230620T103000
SUMMARY:Meeting Canari team and Inria Bordeaux head team
LOCATION:INRIA building\, room George Bool 2
DESCRIPTION:The LFANT seminar is canceled. Instead\, there will be a recur
rent meeting between the team members and the administrative direction. Th
e meeting is not compulsory for the PdD students.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Canari team INRIA":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Canari team
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:d3979c2d-85eb-48be-a9ca-ea49321ff62d
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230627T100000
SUMMARY:White-Box Implementations of ECDSA
LOCATION:salle 1
DESCRIPTION:Cryptographic algorithms are primarily designed to be secure i
n the black-box model\, where an attacker can only observe their input/out
put behavior. However
in practice\, algorithms are rarely executed in a
completely isolated environment
and additional information is often le
aked. In the context of mobile applications or connected objects\, devices
often lack secure storage to protect secret keys\, and their generally op
en execution environment exposes a large attack surface. This hostile envi
ronment is captured by the white-box attack model.
While many white-box
implementation of block ciphers have been published since 2002\, asymmetr
ic cryptosystems have been very little studied. In my PhD thesis\, we got
interested in white-box implementations of ECDSA. This led us to participa
te in the WhibOx Contest that was organized as part of the TCHES workshops
in 2021. During three months\, developpers were invited to submit ECDSA w
hite-box implementations and attackers to try to break them.
In this ta
lk\, I will introduce the white-box model before explaining the specificit
ies of the ECDSA algorithm in this context. I will then present the differ
ent attacks that we used to break almost all the challenges of the WhibOx
Contest.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Agathe Houzelot Labri":MAILTO:null@math.
u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Agathe Houzelot
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:e7074560-b54c-459c-b344-aac12c6e458a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230912T110000
SUMMARY:SQISignHD : Signing with higher dimensional isogenies.
LOCATION:salle 2
DESCRIPTION:The SQISign isogeny-based post-quantum digital signature schem
e introduced by De Feo\, Kohel\, Leroux\, Petit and Wesolowski outputs ver
y compact signatures at the expense of a high signature time. In this pres
entation\, we recall how SQISign works and introduce a new scheme based on
SQISign and the polynomial time torsion point attacks against SIDH due to
Castryck\, Decru\, Maino\, Martindale and Robert to sign with higher dime
nsional isogenies. This scheme remains to be implemented but we expect a s
ignificant signature time improvement\, better security properties and sig
natures even more compact than in the original SQISign scheme.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pierrick Dartois IMB":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pierrick Dartois
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:d46742ad-f30d-4006-b091-5a109f867c36
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230919T110000
SUMMARY:Drinfeld modules in SageMath
LOCATION:salle 2
DESCRIPTION:In this talk\, I will briefly introduce Drinfeld modules which
\, in some sense\, appears as a arithmetically meaningful analogue of elli
ptic curves in the context of function fields. I will then discuss an impl
ementation of Drinfeld modules which was recently included in SageMath. (J
oint work with David Ayotte\, Antoine Leudière and Joseph Musleh.)
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Xavier Caruso IMB":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Xavier Caruso
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6619bc47-115a-4ba7-a865-abc40177197c
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20230926T110000
SUMMARY:Ideal-SVP is Hard for Small-Norm Uniform Prime Ideals
LOCATION:salle 2
DESCRIPTION:The presumed hardness of the Shortest Vector Problem for ideal
lattices (Ideal-SVP) has been a fruitful assumption to understand other a
ssumptions on algebraic lattices and as a security foundation of cryptosys
tems. Gentry [CRYPTO’10] proved that Ideal-SVP enjoys a worst-case to av
erage-case reduction\, where the average-case distribution is the uniform
distribution over the set of inverses of prime ideals of small algebraic n
orm (below d^O(d) for cyclotomic fields\, where d refers to the field degr
ee). De Boer et al. [CRYPTO’20] btained another random self-reducibility
result for an average-case distribution involving integral ideals of norm
2^O(d^2). In this work\, we show that Ideal-SVP for the uniform distribut
ion over inverses of small-norm prime ideals reduces to Ideal-SVP for the
uniform distribution over small-norm prime ideals. Combined with Gentry’
s reduction\, this leads to a worst-case to average-case reduction for the
uniform distribution over the set of small-norm prime ideals. Using the r
eduction from Pellet-Mary and Stehlé [ASIACRYPT’21]\, this notably lead
s to the first distribution over NTRU instances with a polynomial modulus
whose hardness is supported by a worst-case lattice problem.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Joël Felderhoff ENS Lyon":MAILTO:null@m
ath.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Joël Felderhoff
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:121a084e-3e0f-4628-9b4b-3a2b522a803f
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20231003T110000
SUMMARY:An Algebraic Point of View on the Generation of Pairing-Friendly E
lliptic Curves
LOCATION:salle 2
DESCRIPTION:In 2010\, Freeman\, Scott\, and Teske published a well-known t
axonomy compiling the
best known families of pairing-friendly ellipti
c curves. Since then\, the
research effort mostly shifted from the ge
neration of pairing-friendly curves to
the improvement of algorithms
or the assessment of security parameters to resist
the latest attacks
on the discrete logarithm problem. Consequently\, very few new
famil
ies were discovered. However\, the need of pairing-friendly curves of prim
e
order in some new applications such as SNARKs has reignited the int
erest in the
generation of pairing-friendly curves\, with hope of fin
ding families similar to
the one discovered by Barreto and Naehrig.Building on the work of Kachisa\, Schaefer\, and Scott\, we show that
some elements
of extensions of a cyclotomic field have a higher proba
bility of generating a
family of pairing-friendly curves. We present
a general framework which embraces
the KSS families and many of the o
ther families in the taxonomy paper. We finally
introduce a new famil
y with embedding degree k=20 which we estimate to provide
a faster Mi
ller loop compared to KSS16 and KSS18 at the 192-bit security level.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean Gasnier IMB":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean Gasnier
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:dbd358c9-e314-42ca-b23d-ff3a76752a72
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20231010T110000
SUMMARY:A Renormalisation Decoder for Kitaev's Toric Quantum Code
LOCATION:salle 2
DESCRIPTION:Kitaev's toric code is expected to be at the core of the first
generation of quantum computers that will incorporate error protection. T
o make full use of the toric code\, one requires an efficient decoding sch
eme that will process the classical information obtained from quantum synd
rome measurements\, so as to be able to regularly put arrays of qubits bac
k into their intended states. The renormalisation decoders introduced by D
uclos-Cianci and Poulin exhibit one of the best trade-offs between efficie
ncy and speed. One feature that remained a mystery however\, is their beha
viour over adversarial channels\, i.e. their worst-case behaviour. In this
talk\, we introduce a relatively natural and deterministic version of a r
enormalisation decoder and bound its error-correcting radius.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Wouter Rozendaal IMB":MAILTO:null@math.u
-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Wouter Rozendaal
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:605428ee-a136-4497-92b8-91c4a8fd640a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20231024T110000
SUMMARY:On the Galois structure of units of totally real $p$-rational fiel
ds
LOCATION:salle 2
DESCRIPTION:The Galois module structure of algebraic units is fundamental
in number theory. However\, its investigation is difficult because we need
to understand arithmetic of number fields\, and the integral representati
ons of finite groups are difficult to classify. A number field is called $
p$-rational if the Galois group of the maximal pro-$p$ $p$-ramified extens
ion is free pro-$p$. The $p$-rationality is known to be a condition that r
educes the complexities in problems in number theory. In this talk\, we ex
plain our results on the implication of the existing theories on integral
representations of finite groups (factor equivalence\, regulator constant\
, Yakovlev diagram) on the algebraic units of totally real $p$-rational fi
elds. This talk is based on the joint works with Z. Bouazzaoui\, D. Burns\
, A. Kumon\, and C. Maire.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Donghyeok Lim Korea":MAILTO:null@math.u-
bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Donghyeok Lim
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:93ae62d4-5258-42b7-864e-82e937ac2e05
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20231107T110000
SUMMARY:Pseudorandom Correlation Generators from the Hardness of Decoding
Codes over Group Algebras
LOCATION:salle 2
DESCRIPTION:The main bottleneck of secure multiparty computation is the co
st of the communication between all the parties. Nevertheless\, it is know
n for a long time that if prior to the actual MPC protocol\, all the parti
es share random field elements having a useful correlation such as random
multiplication triples\, or the so-called random Oblivious Linear Evaluati
ons (OLE's)\, the parties can engage in a very efficient protocol. The goa
l is therefore to generate this large amount of correlated randomness. To
achieve this goal\, Boyle et al. recently introduced a new tool which they
called "Pseudorandom Correlation Generators" (PCG's) and demonstrated how
it can be used to generate and distribute a large amount of (pseudo)rando
m OLE's to two parties\, using minimal interactions\, followed solely by l
ocal computations. This enables secure two-party computation with "silent
preprocessing"\, which can be extended to N-party using "programmable" PCG
's.
Previous constructions of programmable PCG's for OLE's suff
er from two downsides: (1) They only generate OLE's over large fields\, an
d (2) They rely on a rather recent "splittable Ring-LPN" assumption which
lacks from strong security foundations.
In this talk\, I will p
resent a way to overcome both limitation by introducing the "Quasi-Abelian
Decoding Problem" which generalises the well-known decoding problem of qu
asi-cyclic codes\, and show how its hardness allows to build programmable
PCG's for the OLE correlation over any field Fq (with q>2).
Fin
ally\, if time permits\, I will evoke some ideas towards the q=2 case\, wh
ich involves some elements from the theory of Carlitz modules over F2(T).<
br />
This is based on a joint work with Geoffroy Couteau\, Alain Cou
vreur and Clément Ducros
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Maxime Bombar CWI":MAILTO:null@math.u-bo
rdeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Maxime Bombar
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6e293185-9380-41bc-aa9c-a599519b9930
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20231114T110000
SUMMARY:Computing isomorphism classes and polarisations of abelian varieti
es over finite fields
LOCATION:salle 2
DESCRIPTION:We consider abelian varieties over a finite field which are or
dinary\, or over a prime field\, and which have commutative endomorphism a
lgebra.
Works of Deligne and Centeleghe-Stix allow us to describe the
se abelian varieties in terms of fractional ideals of an order in an étal
e algebra. I will explain how such descriptions can be exploited to explic
tly compute the abelian varieties up to isomorphism.
Moreover\, resul
ts by Howe give us a way to compute principal polarisations of the abelian
varieties in the ordinary case. In a joint work with Bergström and Karem
aker we extend these results to the prime field case.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Stefano Marseglia Utrecht University":M
AILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Stefano Marseglia
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:e7afdc5e-03c2-4e0a-9041-28888703fa6c
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20231121T110000
SUMMARY:Galois representations attached to elliptic curves and Serre's uni
formity question
LOCATION:salle 2
DESCRIPTION:The study of Galois representations attached to elliptic curve
s is a very fruitful branch of number theory\, which led to the solution o
f very tough problems\, such as Fermat's Last Theorem. Given a rational el
liptic curve E\, the representation \\rho_{E\,p} is described by the actio
n of the absolute Galois group of \\mathbb{Q} on the p-torsion points of E
. In 1972 Serre proved that for every rational elliptic curve E without CM
there is a constant N_E such that\, for every prime p>N_E\, the Galois re
presentation \\rho_{E\,p} is surjective. In the same article\, he asked wh
ether the constant N_E is independent of the curve\, and this became known
as Serre's Uniformity Question. In this talk\, I will discuss the current
progress towards the answer to this question\, in particular the Runge me
thod for modular curves\, developed by Bilu and Parent\, and the recent im
provements obtained via this method by Le Fourn--Lemos and Lombardo and th
e speaker.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Lorenzo Furio University of Pisa":MAILTO
:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Lorenzo Furio
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:a2748d45-891b-4813-9bc7-879e5fbef1b3
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20231128T110000
SUMMARY:Disorientation faults in CSIDH
LOCATION:salle 2
DESCRIPTION:In this work\, we investigate a new class of fault-injection a
ttacks against the CSIDH family of cryptographic group actions. Our disori
entation attacks effectively flip the direction of some isogeny steps\, re
sulting in an incorrect output curve. The placement of the disorientation
fault during the algorithm influences the distribution of the output curve
in a key-dependent manner. We explain how an attacker can post-process a
set of faulty outputs to fully recover the private key. We provide full de
tails for attacking the original CSIDH proof-of-concept software as well a
s the CTIDH constant-time implementation. Finally\, we present a set of li
ghtweight countermeasures against the attack and discuss their security. T
his presentation will focus on analysing the graph of faulty curves formed
in the post-processing stage and getting an intuition on how it can be us
ed to infer constraints on the secret key. This is joint work with Gustavo
Banegas\, Juliane Krämer\, Tanja Lange\, Michael Meyer\, Lorenz Panny\,
Krijn Reijnders and Jana Sotáková.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Monika Trimoska Eindhoven University of
Technology":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Monika Trimoska
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c99dd926-5644-4165-b044-d6a95bfd6ba5
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20231205T110000
SUMMARY:Automatic algebraic continued fractions in characteristic 2
LOCATION:salle 2
DESCRIPTION:In this talk I will first introduce automatic sequences and th
eir
link with algebraicity. Then I will present two families of
automatic algebraic continued fractions in characteristic 2.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Yining HU Harbin Institut of Technology
\, China":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Yining HU
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:be1d3c80-b689-480f-bc9f-83579b286a1a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20231212T110000
SUMMARY:Computing 2-isogenies between Kummer lines
LOCATION:salle 2
DESCRIPTION:One of the best arithmetics on elliptic curves involves Montgo
mery xz-coordinates\, which are used in several cryptographic protocols su
ch as ECDSA or ECDH. These coordinates also offer fast computations of 2-
and 4-isogenies\, used in several protocols like it was the case with SIDH
\, both for doubling and images of points\, so improving isogeny formulas
also improves scalar products on an elliptic curve. We realized there was
a more general theory of Kummer lines under which xz-coordinates fall.
In this talk\, we will describe the general framework of Kummer li
nes\, based on two families of examples: Montgomery xz-coordinates and the
ta models. We will then explain how to find 2-isogeny formulas\, whether t
hey were already known or new\, and how we mixed them to improve elliptic
curve arithmetic.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Nicolas Sarkis IMB":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Nicolas Sarkis
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:60340fbe-bee0-4e91-a6cf-7423192f7feb
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20231219T110000
SUMMARY:Pairings\, class groups\, and how (not) to break isogeny-based cry
ptography
LOCATION:salle 2
DESCRIPTION:Maps between elliptic curves\, also called isogenies\, are fix
ed once the image on sufficiently many points is known. Last year\, a meth
od was discovered that computationally recovers isogenies just by knowing
information about their image points\, leading to the break of the key-exc
hange scheme SIDH. Isogeny-based key-exchange proposals relying on class g
roup actions\, such as CSIDH\, remain unaffected\, because such image info
rmation is not directly available. Using the theory of pairings on ellipti
c curves\, we show that sometimes one may recover such information anyway\
, and classify when this approach results in a key-recovery attack.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Marc Houben Leiden University Netherland
s":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Marc Houben
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:b3f51651-f299-4f96-acc7-039195337355
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240116T110000
SUMMARY:Effective aspects of Riemann-Roch spaces in the Hilbert class fiel
d
LOCATION:salle 2
DESCRIPTION:Let $K$ be a finite field\, $X$ and $Y$ two
curves over
$K$\, and $Y\\rightarrow X$ an unramified abelian
cover with Galo
is group $G$. Let $D$ be a divisor on $X$
and $E$ its pullback on
$Y$. Under mild conditions the linear space
associated with $E$ is
a free $K[G]$-module. We study the
algorithmic aspects and applicat
ions of these modules.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jean-Marc Couveignes IMB":MAILTO:null@ma
th.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jean-Marc Couveignes
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:4d2e94de-f2ed-445c-ba49-318c4f3eb56b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240123T110000
SUMMARY:Faster modular composition of polynomials
LOCATION:salle 2
DESCRIPTION:This talk is about algorithms for modular composition of univa
riate
polynomials\, and for computing minimal polynomials. For two un
ivariate
polynomials a and g over a commutative field\, modular compo
sition asks to
compute h(a) mod g for some given h\, while the minima
l polynomial problem is
to compute h of minimal degree such that h(a)
= 0 mod g. We propose algorithms
whose complexity bound improves upo
n previous algorithms and in particular upon
Brent and Kung's approac
h (1978)\; the new complexity bound is subquadratic in
the degree of
g and a even when using cubic-time matrix multiplication. Our
improve
ment comes from the fast computation of specific bases of bivariate
i
deals\,
and from efficient operations with these bases thanks to fast
univariate
polynomial
matrix algorithms. We will also report on
experimental results using the
Polynomial Matrix Library.
Contains joint work with Seung Gyu Hyun\, Bruno Salvy\, Eric Schost\, Gil
les
Villard.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Vincent Neiger Sorbonne Université":MAI
LTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Vincent Neiger
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:0065afba-20a0-4f0b-9068-6a10233c13d2
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240130T110000
SUMMARY:Algorithmic aspects of isogeny-based cryptography
LOCATION:salle 2
DESCRIPTION:One of the main struggles of isogeny-based cryptographic proto
cols is that they are still relatively slow compared to other post-quantum
candidate schemes. In this talk we will provide some info on why this is\
, and elaborate on some of the recent results and ongoing work in this dir
ection.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Thomas Decru Brussels\, Belgium":MAILTO:
null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Thomas Decru
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:0406e9ea-c41e-40b2-b284-1b63497eaf65
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240206T110000
SUMMARY:l-adic point counting on surfaces: nearly almost halfway there?
LOCATION:salle 2
DESCRIPTION:While point counting algorithms on algebraic curves over finit
e fields have been around for decades and seen considerable progress in th
e meantime\, the question of counting points on algebraic surfaces without
additional structure seems much more challenging. In this talk\, we will
present results concerning the classical l-adic method for surfaces fibere
d over the projective line\, which was conjectured by Edixhoven and Couvei
gnes to admit a polynomial-time complexity. This method boils down to comp
uting the étale cohomology of a constructible sheaf: we will describe how
to compute this cohomology once such a sheaf has been given\, and outline
a possible strategy that might allow to compute a usable description of t
his particular sheaf.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Christophe Levrat Télécom Paris":MAILT
O:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Christophe Levrat
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:687700d8-b602-4e7c-a835-fa84b2cea748
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240213T110000
SUMMARY:Approx-SVP in multiquadratic ideal lattices
LOCATION:zoom 87807228123
DESCRIPTION:Multiquadratic fields are exceptional objects in computational
number theory. Many hard computational problems are significantly simpler
there. This includes unit/class group and discrete logarithm computations
\, as well as computing short generators of principal ideals. However\, th
ere are still many open questions in the area. In this talk\, I describe r
ecent progress towards the next milestone -- the approximate shortest vect
or problem in non-principal ideal lattices. In particular\, I present an a
lgorithm for a central subroutine -- the discrete logarithm computation ba
sed on reduction of the problem to subfields
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Semyon Novoselov University of Kaliningr
ad":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Semyon Novoselov
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:7404e3a3-e56d-4ed6-941c-279dbe3dad99
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240220T110000
SUMMARY:Discussion autour du Générateur Sac à dos
LOCATION:salle 2
DESCRIPTION:Le Générateur Sac à dos\, proposé en 1985 par Rueppel et M
assey est un
générateur pseudo aléatoire (PRNG) qui combine un pr
emier PRNG faible\, le
LFSR\, et un problème dur \,le problème de
la somme de sous-ensemble\, dérivé du
problème de sac à dos.
Ce générateur a été attaqué avec succès par Knellwolf et Meyer en
2011. Je
discuterais ici d'une variante plus efficace de ctette atta
que et des différentes
attaques que j'ai pu proposer avec Damien Ve
rgnaud et Charles contre des
variantes de ce générateur.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Florette Martinez Lip6":MAILTO:null@math
.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Florette Martinez
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:86f80f53-2364-465e-94d3-f9f6282ceec6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240227T110000
SUMMARY:Variants of the Decoding Problem and algebraic cryptanalysis
LOCATION:salle 2
DESCRIPTION:The intractability of decoding generic linear codes is at the
core of an important branch of post-quantum cryptography.
In this con
text\, the code is random by design or it is assumed to be so in the secur
ity reduction.
This talk will focus on versions of the Decoding
Problem where the error vector is structured\, in general to achieve bett
er performance.
While combinatorial techniques such as Information Se
t Decoding are often the method of choice to attack these versions\, I wil
l describe the potential of algebraic algorithms.
I will mostly
consider the Regular Syndrome Decoding Problem and a paper presented at E
urocrypt 2023.
I will also mention ongoing work on an assumption used
in the CROSS submission to new call for signature schemes launched by NIS
T.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Pierre Briaud Inria Paris":MAILTO:null@m
ath.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Pierre Briaud
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:58ca8988-8510-48c1-a151-b7561428ca0a
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240305T110000
SUMMARY:Skolem meets Schanuel
LOCATION:salle 2
DESCRIPTION:A linear recurrence of order~$r$ over a number field~$K$ is a
map ${U:\\mathbb{Z}\\to K}$ satisfying a relation of the form
$$
U(n+r)=a_{r-1}U(n+r-1)+ \\cdots+ a_0U(n) \\qquad (n\\in \\mathbb{Z})\, <
br />$$
where ${a_0\, \\ldots\, a_{r-1}\\in K}$ and ${a_0\\ne 0}$. A
linear recurrence is called simple if the characteristic polynomial ${X^r-
a_{r-1}X^{r-1}-\\ldots- a_0}$ has only simple roots\, and non-degenerate i
f ${\\lambda/\\lambda'}$ is not a root of unity for any two distinct roots
$\\lambda\, \\lambda'$ of the characteristic polynomial. The classical Th
eorem of Skolem-Mahler-Lech asserts that a non-degenerate linear recurrenc
e may have at most finitely many zeros. However\, all known proofs of this
theorem are non-effective and do not produce any tool to determine the ze
ros.
In this talk I will describe a simple algorithm tha
t\, when terminates\, produces the rigorously certified list of zeros of a
given simple linear recurrence. This algorithm always terminates subject
to two celebrated conjectures: the $p$-adic Schanuel Conjecture\, and the
Exponential Local-Global Principle. We do not give any running time bound
(even conditional to some conjectures)\, but the algorithm performs well i
n practice\, and was implemented in the \\textit{Skolem tool}
$$
\\text{https://skolem.mpi-sws.org/}
$$
that I will demonstrate.
This is a joint work with Florian Luca\, Joris Nieuwveld\, Joël Ouaknine
\, David Purser and James Worrell.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Yuri Bilu IMB":MAILTO:null@math.u-bordea
ux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Yuri Bilu
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:e3ef10b8-3045-4b0e-986f-ad8bf7e177a5
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240312T110000
SUMMARY:Polynômes linéarisés et cryptographie en métrique rang
LOCATION:salle 2
DESCRIPTION:Le lien entre polynômes linéarisés et codes en métrique ra
ng est connu depuis longtemps puisque les codes de Gabidulin peuvent être
vu comme codes d’évaluation de certains de ces polynômes. Nous donner
ons d’autres constructions et verrons comment la “géométrisation”
des corps finis grâce aux polynômes linéarisés permet de fournir des p
roblèmes qui pourraient être appliqués dans des contextes cryptographiq
ues.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Olivier Ruatta Université de Limoges":M
AILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Olivier Ruatta
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:9e692518-f766-4313-ae0f-69922c14bf74
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240319T110000
SUMMARY:A new approach based on quadratic forms to attack the McEliece cry
ptosystem
LOCATION:salle 2
DESCRIPTION:In this talk\, I will present a novel algebraic approach for a
ttacking the McEliece cryptosystem which is currently at the 4-th round of
the NIST post-quantum standardization process. The contributions are tw
ofold.
(1) A new distinguisher on alternant and Goppa codes working
in a much broader range of parameters than previous distinguishers is int
roduced and its complexity analysed\;
(2) With this approach\, a pol
ynomial-time key recovery attack on alternant and Goppa codes of high-rat
e and under some conditions on their field size and degree is also provide
d.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Rocco Mora CISPA":MAILTO:null@math.u-bor
deaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Rocco Mora
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:c451ba35-60e0-460e-967f-28c1faa165b5
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240326T110000
SUMMARY:From Chudnovsky-type algorithms to locally recoverable codes
LOCATION:salle 2
DESCRIPTION:Chudnovsky's method makes it possible to construct multiplicat
ion algorithms in finite fields with good bilinear complexity\, i.e. a sma
ll number of bilinear multiplications in the base field. However\, their t
otal complexity and the difficulty of efficiently constructing these algor
ithms are unfavorable.
Historically\, these are evaluation/inte
rpolation algorithms using rational points of algebraic curves/rational pl
aces of function fields. Using asymptotically optimal towers\, the existen
ce of algorithms with bilinear complexity that is linear in the degree of
extension has been proven. But these algorithms are not constructible in p
olynomial time.
Another approach is a recursive construction using pl
aces of increasing degrees. It provides algorithms with a quasi-linear bil
inear complexity\, but constructible in polynomial time.
We wil
l introduce a hybrid construction\, taking the best of both strategies to
obtain algorithms with linear bilinear complexity that can be constructed
in polynomial time.
Secondly\, we will see that some locally re
coverable codes\, where the recovery of a corrupted symbol is possible usi
ng a small amount of other symbols\, appear naturally in the recursive con
struction of Chudnovsky-type algorithms. We will define and study these co
des.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Bastien Pacifico LIRMM":MAILTO:null@math
.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Bastien Pacifico
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:b7053649-7c09-4b7d-831f-31b8c0c31671
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240402T110000
SUMMARY:Generation of "independent" points on elliptic curves by means of
Mordell-Weil lattices
LOCATION:salle 2
DESCRIPTION:This talk is devoted to a novel method of generating "independ
ent" points on an ordinary elliptic curve over a finite field of large cha
racteristic. Such points are actively used\, e.g.\, in the Pedersen vector
commitment scheme and its modifications. The conventional generation cons
ists in sampling points successively via a hash function to the elliptic c
urve. The new generation method equally satisfies the NUMS (Nothing Up My
Sleeve) principle\, but it works faster on average. In other words\, inste
ad of finding each point separately\, it is suggested to sample several po
ints at once with a non-small success probability. This means that in prac
tice the new method finishes in polynomial time\, unless one is mysterious
ly unlucky. More precisely\, some explicit formulas participate in derivin
g up to four "independent" points on any curve of j-invariant 0. Such curv
es are known to be very popular in elliptic curve cryptography.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Dmitrii Koshelev supported by Ethereum F
oundation":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Dmitrii Koshelev
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:89c5f973-15f2-4617-84de-a405332a790e
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240409T110000
SUMMARY:TBA
LOCATION:salle 2
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Simona Etinski Inria Paris":MAILTO:null@
math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Simona Etinski
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:df83b2e9-7afe-4cd9-8840-4c4bb67e1897
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240416T110000
SUMMARY:TBA
LOCATION:salle 2
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Fabrice Etienne IMB":MAILTO:null@math.u-
bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Fabrice Etienne
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:6d104b9b-41d1-4a0a-93df-21973629d435
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240430T110000
SUMMARY:TBA
LOCATION:salle 2
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Lars Ran Radboud University":MAILTO:null
@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Lars Ran
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:5dd25e49-ff41-4594-803b-c0667f599c2b
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240507T110000
SUMMARY:TBA
LOCATION:salle 2
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Félix Huber Labri":MAILTO:null@math.u-b
ordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Félix Huber
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:07af5886-3aa0-4cad-a8ee-1fbd7722bd27
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240514T110000
SUMMARY:Bielliptic Shimura curves $X_0^D(N)$ with nontrivial level
LOCATION:salle 2
DESCRIPTION:In this talk\, I explain how we work towards completely classi
fying all bielliptic Shimura curves X_0^D(N) with nontrivial level N\, ext
ending a result of Rotger that provided such a classification for level on
e. This allows us to determine the list of all pairs (D\,N) for which X_0^
D(N) has infinitely many degree 2 points\, up to 3 explicit possible excep
tions. This is joint work with Frederick Saia.
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Oana Padurariu Max-Planck-Institut für
Mathematik Bonn":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Oana Padurariu
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:62c9e211-0eda-4be8-9215-4aa26709a4c6
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240528T110000
SUMMARY:TBA
LOCATION:salle 2
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Jérémie Berthomieu Sorbonne Universit
é":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Jérémie Berthomieu
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:71a7c731-b207-461e-820f-1562cd3931ce
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240611T110000
SUMMARY:TBA
LOCATION:salle 2
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Valentijn Karemaker Utrecht University\,
The Netherlands":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Valentijn Karemaker
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
BEGIN:VEVENT
UID:01482080-06f3-4033-b142-3b2526e2be58
SEQUENCE:0
DTSTAMP:20240328T090825Z
DTSTART;TZID=Europe/Paris:20240625T110000
SUMMARY:TBA
LOCATION:salle 2
ATTENDEE;ROLE=REQ-PARTICIPANT;CN="Maria Corte-Real Santos University Colle
ge London":MAILTO:null@math.u-bordeaux.fr
URL;VALUE=URI:https://www.math.u-bordeaux.fr/imb/seminaire-de-theorie-algo
rithmique-des-nombres
X-SPEAKER:Maria Corte-Real Santos
X-CATEGORIE:Séminaire de Théorie Algorithmique des Nombres
END:VEVENT
END:VCALENDAR