Geometry & Topology

Event Information Cyclic group actions on contractible 4-manifolds
16:10 on Monday April 03, 2017
17:00 on Monday April 03, 2017
BA6183, Bahen Center, 40 St. George St.
Ian Hambleton

McMaster University

There are known infinite families of Brieskorn homology 3-spheres which can be realized as boundaries of smooth contractible 4-manifolds. We use gauge theory to show that free periodic actions on these Brieskorn spheres do not extend smoothly over any such contractible 4-manifold. We give a new infinite family of examples in which the actions extend locally linearly but not smoothly.