CAPITAL REGION ALGEBRA/NUMBER THEORY SEMINAR Speaker: Professor Antun Milas, RPI Time: Wednesday, October 8, at 4:30pm Place: Earth Sciences Bldg. Room 152A, Univ. at Albany Title: Modular Forms, Partitions and Conformal Field Theory Abstract: There is a long history of interest in the theory of partitions. The first discoveries in this theory were made by Euler in the 18th century who studied combinatorial identities by using generating functions (or infinite q--series) for partitions. It turns out that many generating functions exhibit modular properties and this fact links them with the theory of modular forms and modern number theory. Independently, by using ideas from the theory of infinite-dimensional Lie algebras Macdonald reinterpreted many properties of q-series and combinatorial identities in a completely new fashion. However, Macdonald's work did not explain why certain q--series associated to representations of infinite-dimensional Lie algebras exhibit modular properties. Surprisingly, the answer to this question came from physics (more precisely from string theory and conformal field theory). In the first part of my talk I will give a friendly introduction to the theory of partitions, explain what is the Dedekind eta function and briefly explain notions such as modular invariance, modularity, etc. In the second part I shall explain (at least in informal way) why the conformal field theory provides understanding of the mysterious relationship between representation theory of infinite-dimensional Lie algebra and modular forms. I will finish with a few applications based on my recent work. Refreshments at 4:15 pm in ES 152.