Online Talk

There are examples of pairs of closed  aspherical 4-manifolds which are homeomorphic but not diffeomorphic. The construction is based on examples of Hayden and Piccirillo of pairs of aspherical 4-manifolds with boundary which have the with the same property desired in the case of closed manifolds. Although these examples are homotopy equivalent to a 2-torus, they are distinguished from each other by the minimal genus of a smoothly embedded surface that represents the generator of second homology. The Reflection Group Trick is then applied to get these examples of closed  aspherical 4-manifolds. This is joint work with Kyle Hayden, Jingyin Huang, Danny Ruberman and Nathan Sunukjian.