Chennai Mathematical Institute


3:30 pm, Seminar Hall
L^1 full groups for measure-preserving transformations

Francois Le Maitre
University of Paris VII.


Topological full groups of minimal homeomorphisms have attracted a lot of attention, since they (or rather, some of their derived groups) provided the first examples of simple finitely generated infinite amenable groups, as shown by Juschenko and Monod. In this talk, I will present measurable analogues of these groups called L^1 full groups associated to a measure-preserving ergodic transformation. After explaining their basic properties, I will sketch a proof of the following result: the L^1 full group of an ergodic measure preserving transformation has a finitely generated dense subgroup if and only if the transformation has finite entropy.