Symmetries of 4-manifolds

The striking differences between smooth and topological 4-manifolds are also reflected in their symmetries. It seems that smooth 4-manifolds tend to be much more "rigid" than their topology predicts, particularly from the view-point of the finite groups of symmetry. One explanation may be that smooth 4-manifolds have extra "hidden" constraints on their symmetry arising from gauge theory, i.e. the moduli spaces of solutions for certain PDEs on the manifold. In this talk we will describe some examples of this principle in operation, and mention some open problems.

Refreshments will be served at 2:45 p.m. in the Faculty Lounge, Math Annex (Room 1115).