Wednesday, May 13, 2020

2020-05-20 / 09:00 ~ 10:30

학과 세미나/콜로퀴엄 - 위상수학 세미나: Actions of Homeo and Diffeo groups on manifolds

by Lei Chen(Caltech)

In this talk, I discuss the general question of how to obstruct and construct group actions on manifolds. I will focus on large groups like Homeo(M) and Diff(M) about how they can act on another manifold N. The main result is an orbit classification theorem, which fully classifies possible orbits. I will also talk about some low dimensional applications and open questions. This is a joint work with Kathryn Mann.

2020-05-13 / 16:00 ~ 17:30

학과 세미나/콜로퀴엄 - 위상수학 세미나: Big mapping class groups acting on homology

by Federica Fanoni(CNRS)

To try and understand the group of symmetries of a surface, its mapping class group, it is useful to look at its action on the first homology of the surface. For finite-type surfaces this action is fairly well understood. I will recall what happens in this case, introduce infinite-type surfaces (surfaces whose fundamental group is not finitely generated) and discuss joint work with Sebastian Hensel and Nick Vlamis in which we describe the action on homology for these surfaces.

Events for the 취소된 행사 포함