TITLE: Partitions, Algebraic Geometry and Representation Theory

ABSTRACT:
We use the Hilbert schemes of points on complex surfaces to illustrate interplay among combinatorics, algebraic geometry and representation theory. The basic model is the Hilbert schemes of points on the complex plane, whose Euler characteristics coincides with the number of partitions. Its cohomology group follows from H. Nakajima's construction of an infinite dimensional Heisenberg algebra action. For the Hilbert schemes of points on an arbitrary complex surface, we review the main results obtained in a series of joint papers (with W.-P. Li and W. Wang) via vertex algebra techniques and their connections with works of A.
Okounkov and R. Pandharipande. We end with a discussion of Y. Ruan's Cohomological Crepant Resolution Conjecture for these Hilbert schemes.