Geometry & Topology Seminar

Speaker: Kyle Hayden (Rutgers University Newark) Title: Disordered handles and the complexity of h-cobordisms Abstract: How do you measure the distance between exotic smooth structures on the same 4-manifold? One natural measure is the complexity of an h-cobordism between them. In this talk, I will compare several notions of complexity for h-cobordisms and discuss their relevance to studying 4-manifolds up to stable diffeomorphism. The main new ingredient is a surprising connection between the number of critical points on the h-cobordism and the order in which they appear.