Archive for Boltzmann-Grad limit

d≥3 strikes again

Posted in Statistics, University life with tags , , , , , , , , , , on April 23, 2024 by xi'an

Yesterday, Bálint Tóth (University of Bristol and Alfréd Rényi Institute of Mathematics) came to Paris Dauphine for a seminar on the Botlzmann-Grad limit and the existence of a central (double) limit theory. Which was somewhat related with the above video of an earlier seminar, albeit without the first part on the historical roots of the problem. This was a brilliant talk as quite accessible to the entirety of the lab, while providing detailed entries on the mechanism leading to the CLT, in particular the substitution of the physical process by a Markovian(ised) process that stayed closed enough to the original for long enough, a sort of (anti-)coupling idea I had never met before. The other (personally) striking feature of the seminar was the occurrence of the boundary d=3 on the dimension of the process, The same boundary as in the Stein phenomenon (and the difference from recurrent to transient in random walks). But I could not see a clear connection with the present challenge.