# Current and Recent Colloquia

**Distinguished Colloquium**

Tuesday, August 26, at 3 p.m.

Auditorium SN-2109

**Victor Kac**

Massachusetts Institute of Technology

**“Ramanujan mock theta function and representations of****infinite-dimensional Lie superalgebra”**

**Abstract.** In his last letter to Hardy in 1920, Ramanujan listed 17 functions, which he called "mock theta functions" since they behave like theta functions but have no modular invariance properties of theta functions. Since then there have been substantial progress in understanding of mock theta functions.

About 10 years ago, Zwegers introduced non-holomorphic corrections, which made these functions modular. In the recent work with Wakimoto, we linked mock theta functions to representation theory of affine Lie superalgebras. This in turn sheds new light on the theory of mock theta functions.

On November 28, 2012 from 1-2 pm in room HH-3017, Dr. Yuanlin Li (Brock University) will give an AAC Colloquium talk "**Zero-divisor Graphs of Group Rings". **This talk is joint with Dr. Farid Aliniaeifard (Brock University).

The abstract for this talk is available here.

On February 1, 2012, Dr. Eduardo Martinez-Pedroza (Memorial University) gave an AAC Colloquium Talk "**Residual finiteness, subgroup separability and non-positively curved groups**"

In this talk the notions of residual finiteness and subgroup separability were discussed in connection with non-positively curved groups. Research on non-positively curved groups is motivated by the study of lattices in real rank one semi-simple Lie groups and manifold topology. Open questions, motivation, and some of my work in the area were discussed.

On November 16, 2011 Dr. Sara Faridi (Dalhousie University) gave an AAC Colloqium talk "**Combinatorics and Commutative Algebra**"

That talk was about using graphs and hypergraphs to study questions in commutative algebra. Dr. Faridi discussed how problems in commutative algebra had led to the description of combinatorial structures that seemed to fit surprisingly well in the existed combinatorics literature. She also discussed open questions, and what the answers "should" look like.

On January 12, 2011 Professor Hugh Thomas of University of New Brunswick - Fredericton gave a Distingushed Colloquium Talk entitled **"Garside structures for braid groups". **

**“SINGULAR and Applications”.**