 He was previously a professor at Princeton University from 2002 to 2010, an assistant and associate professor at the University of California, Berkeley, and an instructor at the University of Chicago.He has worked on the representation theory of infinite symmetric groups, the statistics of plane partitions, and the quantum cohomology of the Hilbert scheme of points in the complex plane.Much of his work on Hilbert schemes was joint with Rahul Pandharipande.