School of Mathematics

A Reidemeister-Singer Conjecture for Surface Diagrams

Jonathan Williams
University of California, Berkeley
December 3, 2010

There is a way to specify any smooth, closed oriented four-manifold using a surface decorated with simple closed curves, something I call a surface diagram. In this talk I will describe three moves on these objects, two of which are reminiscent of Heegaard diagrams for three-manifolds. These may form part of a uniqueness theorem for such diagrams that is likely to be useful for understanding Floer theories for non-symplectic four-manifolds.

The Permanents of Gaussian Matrices

Scott Aaronson
Massachusetts Institute of Technology
November 29, 2010

In recent joint work with Alex Arkhipov, we proposed a quantum optics experiment, which would sample from a probability distribution that we believe cannot be sampled (even approximately) by any efficient classical algorithm, unless the polynomial hierarchy collapses. Several optics groups are already working toward doing our experiment.