Title：Modular invariants for proper actions

Speaker：韩 飞  （新加坡国立大学）

Time：2019年4月22日     下午  16:30-17:30

Room：东区第五教学楼  5507室

Abstract：In this talk, we will present our work on open Lie group actions on open manifolds. Witten genus and elliptic genera are modular topological invariants for manifolds, which are closely related to representation of loop groups and the hypothetical index theory on free loop spaces as well as the elliptic cohomology theory in algebraic topology. They find applications in problems of positive curvature and group actions on manifolds. In this talk, we will briefly introduce these invariants and present our joint work with Varghese Mathai on generalizing them to open manifolds with proper actions of open Lie groups.