Title: Homotopy of Diffeomorphism Groups

Speaker: Dave Auckly

Abstract: There is an invariant that can detect non-trivial and exotic elements of the fundamental group of the group of diffeomorphism group of certain sums of projective spaces. We will discuss a method to compute this invariant based on a dog-bone/wall-crossing argument. Given interest we will compare this wall crossing with the wall-crossing that appears in Donald-Thomas theory.