Non-Commutative Boundaries and Characters on Lattices and Commensurators
Jesse Peterson, Vanderbilt University
Location: Stevenson 1432
A character on a group is a function of positive type which is invariant under conjugation. The study of characters on group was initiated with the work of Thoma, and is closely connected to the study of II_1 factors, especially in the presence of rigidity phenomena. I will discuss recent joint work with Darren Creutz, where we investigate the classification of characters on lattices and commensurators in semi-simple groups via non-commutative Poisson boundaries of II_1 factors.