Walter Neumann of Barnard College / Columbia University gives a presentation at the 50th annual Cornell Topology Festival, May 7, 2012. Neumann addresses the local metric geometry at a point of a complex surface in terms of a collection of rational numbers associated to components of a refined JSJ decomposition of the 3-manifold link of the point.

The festival was organized by the Cornell University Department of Mathematics with support from the National Science Foundation.