Speaker: Thomas Koberda
Date: August 10, 2017
Affiliation: University of Virginia, USA

Abstract: I will discuss some aspects of the algebraic structure of finitely generated groups of diffeomorphisms of compact one-manifolds. In articular, we show that if $G$ is not virtually metabelian then $(G \times Z)*Z$ cannot act faithfully by $C^2$ diffeomorphisms on a compact one-manifold. Among the consequences of this result is a completion of the classification of right-angled Artin groups which admit faithful $C^{\infty}$ actions on the circle, a program initiated together with H. Baik and S. Kim. This represents joint work with S. Kim.