Special Colloquium
Robin Tucker-Drob
Rutgers University
Treeability and planarity in measured group theory
Abstract: A probability measure preserving (p.m.p.) action of a group G is said to be treeable if the orbits of the action can be measurably structured by trees. A countable group G is called treeable if it has a free p.m.p. action which is treeable. The group G is called strongly treeable if all of its free p.m.p. actions are treeable. I will discuss recent joint work with C. Conley, D. Gaboriau, and A. Marks in which we show that finitely generated groups with planar Cayley graphs (e.g., surface groups) are strongly treeable. This provides the first examples of strongly treeable groups which are not obtained from amenable groups by applying the obvious operations which preserve strong treeability, such as taking free products.
There is a Meet & Greet Tea right after the talk in SEO 300.
Tuesday January 20, 2015 at 3:00 PM in SEO 636