Branched covers and nonpositive curvature

Series: 
Geometry Topology Seminar
Friday, November 7, 2008 - 14:00
1 hour (actually 50 minutes)
Location: 
Skiles 269
,  
School of Mathematics, Georgia Tech
Organizer: 
In the 1980s Gromov showed that curvature (in the triangle comparison sense) decreases under branched covers. In this expository talk I shall prove Gromov's result, and then discuss its generalization (due to Allcock) that helps show that some moduli spaces arising in algebraic geometry have contractible universal covers. The talk should be accessible to those interested in geometry/topology.