Current

The seminar is held on Tuesdays from 11 to 12 and is organised by Sabrina Kunzweiler and Maxime Bombar. Unless stated otherwise it takes place in room 2 of IMB. To get announcements, you can subscribe to the mailing list of the Bordeaux number theory seminars. Last minute changes may appear first on the IMB website.

• 2025-05-27
  11:00
  Salle 2
  Jonathan Komada Eriksen (KU Leuven)
  Qlapoti: Simple and Efficient Translation of Quaternion Ideals to Isogenies
  One of the most important building blocks in isogeny-based cryptography is an algorithm for translating ideals to their corresponding isogenies. The current state of the art for quaternion ideals is an approach that is based on Clapoti, which is the main part of both signing and key generation in both SQIsign and PRISM. In this talk, we will have a look at the issues with the current algorithm, specifically how the non-negligible failure rate affects both the performance and security proofs. We then present Qlapoti, a new approach that also builds on Clapoti, but is more specialised to quaternion ideals. We will then have an in-depth look at Qlapoti and its failure rate, and show how it solves the remaining issues with the current ideal to isogeny algorithms, while also making key generation and signing in SQIsign/PRISM around 2x faster.
• 2025-06-03
  11:00
  Salle 2
  John Voight (University of Sydney)
  17T7 is a Galois group and abelian fourfolds
  We explicitly realize the group 17T7, an extension of SL(2,16) by $C_2$, as a Galois group over the rationals. The group arises from the field of definition of the 2-torsion on an abelian fourfold with real multiplication defined over a real quadratic field. We find such fourfolds using Hilbert modular forms, first numerically, then certifying the result with exact methods.
• 2025-06-03
  14:00
  Salle de conférences
  Aurel Page (CANARI)
  Hecke operators in algorithmic number theory
  Habilitation à diriger des recherches
• 2025-06-17
  11:00
  Salle 2
  Elena Kirshanova (Technology Innovation Institute, Abu Dhabi)
  TBA
• 2025-06-20
  15:30
  Salle de conférences
  Anne-Edgar Wilke (CANARI)
  Arithmetic group actions: reduction theories and enumeration algorithms
  Soutenance de thèse
• 2025-07-07
  14:00
  Salle de conférences
  Fabrice Étienne (CANARI)
  Algorithmic applications of Hecke operators of finite groups for Galois representations
  Soutenance de thèse
• 2025-07-08
  14:00
  Salle de conférences
  Agathe Beaugrand (CANARI)
  Arguments à divulgation nulle de connaissance efficaces et succincts
  Soutenance de thèse
• 2025-07-09
  10:00
  Salle 1
  Nicolas Sarkis (CANARI)
  Arithmetic of Kummer lines and surfaces
  Soutenance de thèse
• 2025-07-09
  14:00
  Salle 1
  Pierrick Dartois (CANARI)
  Fast computation of higher dimensional isogenies for cryptographic applications
  Soutenance de thèse
• 2025-07-10
  11:00
  Salle 1
  Jean Gasnier (CANARI)
  Arithmétique et algorithmique des courbes algébriques et applications aux codes correcteurs et à la cryptographie
  Soutenance de thèse