[Binghamton Geometry/Topology Seminar] Geometry/Topology Colloquium Thursday October 31

[pedro at math.binghamton.edu]

There will be no seminar talk this Thursday at 2:50PM. Instead we will
have a Colloquium at 4:30PM.


                            COLLOQUIUM

Date:  Thursday October 31st
Time:  4:30-5:30 pm
Place:  Library North 2205

Speaker: Jim Davis (Indiana University)
Title: Rigidity

Abstract: This is a largely expository talk on known topological
obstructions to nonpositive curvature. We shall first explore geometric
meaning of nonpositive curvature and explain why it forces the manifold to
be covered by a Euclidean space. We also discuss the uniformization of
surfaces, and significance of metric completeness, after which we move to
more delicate obstructions coming from harmonic map superrigidity, random
groups with fixed point properties, and elementary group actions.  The
best example of topological rigidity is the Borel Conjecture, which states
that two closed aspherical manifolds with isomorphic fundamental groups
are homeomorphic. The talk will conclude with a discussion of
the equivariant rigidity problem and recent joint work with Connolly and
Khan.