Penn Arts & Sciences Logo

Geometry-Topology Seminar

Thursday, February 17, 2011 - 4:00pm

John Etnyre

Georgia Tech

Location

University of Pennsylvania

DRL 3C8

Note special time and room. This is a joint seminar with PATCH. Tea and refreshments at 5 PM and second talk at 5:30.

We establish an analog of the sphere theorem in the setting of contact geometry. Specifically, if a given three dimensional contact manifold admits a compatible Riemannian metric of positive 4/9-pinched curvature then the underlying contact structure is tight. The proof is a blend of topological and geometric techniques. A necessary technical result is a lower bound for the radius of a tight ball in a contact 3-manifold. We will also discuss geometric conditions in dimension three for a contact structure to be universally tight in the nonpositive curvature setting. This is joint work with Rafal Komendarczyk and Patrick Massot.