Geometry & Topology

Event Information Proper proximality in non-positive curvature
16:10 on Monday December 09, 2019
17:00 on Monday December 09, 2019
BA6183, Bahen Center, 40 St. George St.
Camille Horbez

Université Paris Sud

Motivated by questions concerning the rigidity of certain von Neumann algebras associated to groups or group actions, Boutonnet, Ioana and Peterson recently introduced the notion of proper proximality of a countable group. I will describe this notion and the motivations behind it, and explain how techniques from geometric group theory can be used to show that certain nonpositively curved groups, including rank one CAT(0) groups and mapping class groups, are properly proximal. This is a joint work with Jingyin Huang and Jean Lécureux.