Coup-fourré with Gauss Bonnet

Chris Moseley, Calvin College

If we stretch or squeeze a surface, the topology doesn't change, but the local curvature certainly does.  So "topology doesn't care about curvature," and yet there is a deep relation between the two, expressed in the remarkable Gauss-Bonnet theorem.  I will explain what geometers mean when they talk about the curvature of a surface, what topologists mean by the "genus" of a surface, and how Gauss-Bonnet connects these two quantities.

 Refreshments precede the talk at 3:30 p.m. in NH 282.