Smooth Structures on Closed Four-Manifolds with Non-Trivial Fundamental Group - March 27, 2025

This lecture by András Stipsicz explores the fascinating topic of smooth structures on closed four-manifolds with non-trivial fundamental group. Delve into a key question in four-dimensional topology: determining which closed topological four-manifolds can support multiple or even infinitely many smooth structures. Examine various constructions for producing 'exotic' smooth structures, which provide satisfactory answers in certain cases involving non-trivial fundamental groups. The 49-minute presentation also investigates potential sources of exoticness through the genus function on the second homology group. Presented by the Simons Foundation, this mathematical exploration offers valuable insights into advanced topological concepts.