Séminaires

Informations disponibles à l’adresse : https ://iecl.univ-lorraine.fr/semaine-de-la-recherche-a-la-decouverte-des-medailles-fields-2026-quatre-laureats-pour-illustrer-la-diversite-des-mathematiques/

Jean-Michel Bismut’s hypoelliptic Laplacian is a one-parameter family of linear differential operators that interpolates between the Laplacian on a Riemannian manifold and the generator of the geodesic flow on its tangent bundle. Bismut has analyzed the hypoelliptic Laplacian in a variety of contexts, but in this lecture I shall concentrate on Lie groups and symmetric spaces. In this context, the heat supertraces associated to the operators in the hypoelliptic Laplacian family remain constant throughout the interpolation.  By studying the limits at both ends of the family, remarkable formulas are obtained, including for example the Selberg trace formula. I shall explain a few of the basic ideas underlying Bismut’s method, as re-worked by Shiqi Liu, Ed McDonald, Fedor Sukochev, Dima Zanin and myself in ongoing work.

The purpose of this talk is to introduce locally conformal symplectic manifolds and explain the ideas and main ingredients of the proof of a h-principe for those structures obtained in a joint work with Gael Meigniez.

We give explicit upper and lower bounds on the size of the coefficients of the modular polynomials $\Phi_N$ for the $j$-invariant. These bounds make explicit the best previously known asymptotic bounds. This is joint work with Fabien Pazuki and Florian Breuer.

Numeration 2026 is the 2026 edition of a series of events around numeration systems and substitution systems. The central themes of this conference include (but are not limited to): number theory, diophantine approximation, fractal geometry, substitutions, combinatorics on words, ergodic theory, dynamical systems, and theoretical computer science.

Découvrir le programme
—  Conference website —
https://numeration2026.sciencesconf.org/

— Invited speakers (confirmed) —
Michael Baake, Bielefeld University, Germany
Ayreena Bakhtawar, Polish Academy of Sciences, Poland
Colin Faverjon, University of Picardy Jules Verne, Amiens, France
Lukas Spiegelhofer, Technical University of Leoben, Austria
Manon Stipulanti, University of Liège, Belgium

— Scientific Committee —
– Shigeki Akiyama, University of Tsukuba, Japan
– Valérie Berthé, IRIF, France
– Charlene Kalle, University of Leiden, Netherlands
– Lingmin Liao, University of Wuhan, China
– Edita Pelantová, Czech Technical University, Czech Republic
– Michel Rigo, University of Liège, Belgium
– Wolfgang Steiner, IRIF, France
– Cathy Swaenepoel, University of Paris Cité, France
– Jörg Thuswaldner, Technical University of Leoben, Austria

— Organizing Committee — 
– Cécile Dartyge (IECL, University of Lorraine, France)
– Damien Jamet (LORIA, University of Lorraine, France)
– Manfred Madritsch (Technical University of Leoben, Austria)
– Thomas Stoll (IECL, University of Lorraine, France)

— Past editions —
The previous « Numeration » conferences have been in:
– Tsukuba (2025)
– Utrecht (2024)
– Liège (2023, 2011)
– Vienna (2019)
– Paris (2018)
– Rome (2017)
– Prague (2016, 2008)
– Nancy (2015)
– Debrecen (2014)
– Kyoto (2012)
– Leiden (2010)
– Marseille (2009)
– Graz (2007)
– Grenoble (2005)