Smooth structures on 4-manifolds and corks

Geometry Topology Working Seminar
Friday, September 23, 2016 - 14:00
1.5 hours (actually 80 minutes)
Skiles 006
Georgia Tech
I will discuss a process called a cork twist for relating homeomorphic but not diffeomorphic smooth 4-manifolds. This involves finding a contractible submanifold of a given 4-manifold, removing it, and re-gluing by a diffeomorphism of the boundary. This is a surprisingly simple way of relating non-diffeomorphic manifold that was discovered in the 1990s but has recently been getting a lot of attention.