07/20: Federico Rodriguez Hertz
Non-rigidity of partially hyperbolic abelian 
-actions on tori
Abstract: Joint with Zhiren Wang we show some small
Month: July 2020
07/13: Sebastian Hensel
Quasi-morphisms on surface diffeomorphism groups
Abstract: We will construct nontrivial quasimorphisms on the group of diffeomorphisms of a surface of genus at least 1 which are isotopic to the identity. This involves considering the graph whose vertices
correspond to curves on the surface (not up to isotopy!), and transferring usual curve graph methods to this setting. In particular, we show that it is hyperbolic, and we construct elements of Diff_0(S) which act as independent enough hyperbolic elements on it. As a consequence, we also solve a question by Burago-Ivanov-Polterovich on the unboundedness of the fragmentation norm. This is joint work with Jonathan Bowden and Richard Webb.