Type: Seminar

Distribution: World

Expiry: 14 Feb 2011

Auth: athomas(.pmstaff;2039.2002)@p615.pc.maths.usyd.edu.au

The next Infinite Groups Seminar will be held at the University of Newcastle on Monday 14 February. The schedule is below. Please get in touch if you are interested in getting the train to/from Newcastle with me - Anne. ----- The seminar will be held in Room V206 of the Mathematics building and the two talks will be at 12:00 and 2:00. 12:00 George Willis, University of Newcastle TITLE: Rigidity of Homomorphisms from Arithmetic Groups to Totally Disconnected Groups ABSTRACT: The talk will explain joint work with Yehuda Shalom showing that the only homomorphisms from certain arithmetic groups to totally disconnected, locally compact groups are the obvious, or naturally occurring, ones. For these groups, this extends the supperrigidity theorem that G. Margulis proved for homomorphisms from high rank arithmetic groups to Lie groups. The theorems will be illustrated by referring to the groups $SL_3(\mathbb{Z})$, $SL_2(\mathbb{Z}[\sqrt{2}])$ and $SL_3(\mathbb{Q})$. 2:00 Adam Piggott, Bucknell University TITLE: The automorphisms of McCullough-Miller space ABSTRACT: McCullough-Miller space X = X(W) is a topological model for the outer automorphism group of a free product of groups W. We will discuss the question of just how good a model it is. In particular, we consider circumstances under which Aut(X) is precisely Out(W).