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.

• 2026-11-17
  11:00
  Salle 2
  Jonathan Tilling Niemann (Danmarks Tekniske Universitet)
  Uniqueness of the maximal function field with the third largest genus in characteristic 3
  For a prime power $q$, a function field of genus $g$ over $\mathbb F_{q^2}$ is said to be maximal if it attains the Hasse–Weil upper bound, i.e., if it has exactly $q^2+1+2gq$ places of degree 1. It is well known that the largest possible genus for a maximal function field is $g_1:=q(q−1)/2$, and that the Hermitian function field is the unique maximal function field of this genus up to isomorphism. The second and third largest possible genera are known to be $g_2:=⌊(q−1)2/4⌋$ and $g_3:=⌊(q2−q+4)/6⌋$, and uniqueness is also known for $g_2$. In this talk, we will present a recent result establishing that there is also just one maximal function field of genus $g_3$ in the case where $q$ is a power of 3. The talk is based on joint work with Peter Beelen and Maria Montanucci.
• 2026-11-24
  11:00
  Salle 2
  Piotr Bacik (Oxford University and Max-Planck-Institut Saarbrücken)
  Twisted Rational Zeros and Local-Global Principles for Linear Recurrence Sequences
  In 1934, Skolem conjectured the exponential local-global principle; that a linear recurrence sequence (LRS) has an integer zero if and only if it has a zero modulo every integer $m$. An interesting counterexample shows that a natural strengthening of the Skolem Conjecture, where we restrict $m$ to be a prime power, is false. The failure in this example is accounted for by the relationship between $p$-adic zeros of LRS and twisted rational zeros (introduced by Bilu et al. (2025)). I will talk about some results which may be extracted by studying this relationship further, in particular, a local-global principle for simultaneous zeros of two coprime LRS, subject to the $p$-adic Schanuel Conjecture. A fundamental step in proving this result is characterising when twisted rational zeros are (or are not) $p$-adic zeros for infinitely many primes $p$, which may be done unconditionally. This addresses two questions of Bilu et al. (2025).
• 2026-11-26
  14:00
  Salle 285
  Michael Schaller (Universität Zürich)
  TBA
• 2026-12-08
  11:00
  Salle 2
  Guilhem Mureau (Université du Luxembourg)
  TBA
• 2026-12-15
  11:00
  Salle 2
  Clément Ducros (CISPA Helmholtz-Zentrum für Informationssicherheit)
  TBA