Nir Lazarovich: "Flexible Stability of Surface Groups"

mardi 16 mars 2021, 10:15 → 11:15 Europe/Paris

Abstract: Roughly speaking, a finitely presented group is said to be (flexibly) stable if any approximate action of the group on a finite set is an approximation of an action. Stability is closely related to local testability (in CS), soficity of groups, and residual finiteness. In this joint work with Arie Levit and Yair Minsky, we show that surface groups are flexibly stable using the geometry of CAT(-1) spaces and a new quantitative variant of LERF.