# Seminar talks

- Dynamical systems seminar in MSU, mech-math (Yu. S. Ilyashenko).
- Seminar of the Department of Differential Equations Steklov Mathematical Institute (Dm. V. Anosov, Yu. S. Ilyashenko).
- Ergodic theory and statistical physics in MSU, mech-math (B.M.Gurevich, V.I.Oseledets, S.Pirogov)

**February 22, 2012,** 18h30, MSU, mech-math, room 13-20.

**Isabelle Gallagher** *Some results on the convergence from Newtonian to Boltzmann dynamics.*

*Abstract:*
The Boltzmann equation is known to derive from the Newtonian equations of a large system of particles, obeying elastic collisions or submitted to a repulsive short-range potential, in the limit when the number of particles goes to infinity under a rarefaction assumption. In this talk we shall give the main steps of the rigorous derivation of this equation; unfortunately to this day this derivation is only known for a very short time (roughly a fraction of the time after which each particle has undergone O(1) collisions) and the question of extending the result to larger times is an important, open question.