Adrien le Boudec: Dynamics in Chabauty space and C*-simplicity

Speaker: Adrien le Boudec

Title: Dynamics in Chabauty space and C*-simplicity

Abstract: If G is a countable group, the space of all subgroups of G is naturally a compact space, called the Chabauty space of G, on which G acts by conjugation. The talk will be about uniformly recurrent subgroups (closed, G-invariant, minimal subspaces of Sub(G)) of groups admitting a so-called micro-supported action on a topological space. Examples of such groups are Thompson groups (on the interval, the circle and the Cantor space), piecewise projective groups recently considered by Monod, branch groups, or topological full groups acting minimally on the Cantor space. By work of Kalantar-Kennedy and Breuillard-Kalantar-Kennedy-Ozawa, our results have applications to the study of simplicity of the reduced group C*-algebra of these groups. Joint work with Nicolas Matte Bon.