Topology Seminar

Date: October 20, 2021

Time: 4:00PM - 5:00PM

Location: Zoom

Speaker: Chris Gerig, Simons Center for Geometry and Physics, Stony Brook University

Title: Studying 4-spheres using near-symplectic geometry and ECH

Abstract: I will introduce certain 2-forms that are "nearly symplectic" and use ECH (embedded contact homology) to probe homotopy 4-spheres. The “invariants” built for homotopy 4-spheres will count pseudoholomorphic curves in the complement of circles, but at the moment they are not sensitive enough to distinguish/detect 4-spheres: I will discuss ideas to possibly refine these “invariants”.