The greatest use of the Hahn-Banach theorem ever

Rohil Prasad, Princeton University
Fine Hall 314

In-Person Talk 

Let F denote a smooth p-dimensional foliation of a manifold M. Nearly fifty years ago, Dennis Sullivan used the Hahn-Banach theorem to demonstrate a duality between closed p-dimensional currents tangent to F and closed p-dimensional forms positive on the leaves of F. This turns out to be very useful.