For the end of the Bézout Labex, a scientific meeting is organized, on the campus of Cité Descartes, Marne-la-Vallée (RER Noisy-Champs) – amphithéâtre Maurice Gross, ground floor of bâtiment Copernic, where some among the people that were important to the Labex are invited to give a talk: former members, invited professors and students.
Schedule, November 19, 2024
9h welcome coffee
9h30 Djalil Chafaï (DMA, ENS – PSL): Aspects of the Cutoff Phenomenon for Diffusions.
10h15 Hélène Langlois (LAMA): Kernels and quasi-kernels in directed graphs
10h45 coffee break
11h15 Sylvia Serfaty (Courant Institute, New-York)
12h Evgenii Chzhen (CNRS, Orsay)
12h30 lunch (mandatory registration)
14h Leonid Pastur (King’s college, London)
14h45 Uli Wagner (Institute of Science and Technology Austria)
15h30 coffee break
16h Lucia Caramellino (Universita Tor Vergata, Roma)
16h45 Xavier Goaoc (Université de Lorraine, Nancy)
Abstracts:
Djalil Chafaï (DMA, ENS – PSL): Aspects of the Cutoff Phenomenon for Diffusions.
Abstract: The cutoff phenomenon, conceptualized in the context of finite Markov chains, states that for certain linear evolution equations, started from a point, the distance towards a long time equilibrium may become more and more abrupt in high dimensional state spaces and for certain choices of initial conditions. This can be seen as a critical competition between trend to equilibrium and initial condition. This talk is about the cutoff phenomenon for a few classes of linear and nonlinear diffusions.
Hélène Langlois (LAMA): Kernels and quasi-kernels in directed graphs.
Abstract: In directed graph theory, a kernel is an independent subset of vertices that absorbs every outside vertex. While certain graphs, like directed perfect graphs without directed cycles of length 3, ensure the existence of a kernel, the algorithmic complexity of finding one in this class remains an open question. This presentation explores recent advances in the search for kernels and also discuss quasi-kernels, a concept introduced by Chvátal and Lovász, which exist in all directed graphs but have not been thoroughly studied algorithmically. Key questions will be addressed, such as the minimal size of a quasi-kernel, inspired by a conjecture by Erdős and Székely.
Organization
Scientific committee: Raphaël Danchin, Matthieu Fradelizi, Benjamin Jourdain, Cyril Nicaud
Organizing committee: Matthieu Fradelizi, Nathalie Gambiny, Cyril Nicaud,