Geometry & Topology Seminar: The period map for smooth 4-manifolds

Abstract: The period map of a smooth 4-manifold assigns to a Riemannian metric the space of self-dual harmonic 2-forms.  This map is from the space of metrics to the Grassmannian of maximal positive subspaces in the second cohomology. It is conjectured that the period map is always surjective. I'll explain a proof of this conjecture for 4-manifolds with b^+ = 1, as well as some results that address the more general case.

Host: Ali Daemi