The Ohio State University

Time

May 29 2008 - 2:30pm - 3:30 pm

Location

MW 154

Speaker

Qi Chen (Winston-Salem State University)

Abstract

We will discuss how to obtain integral TQFTs from finite dimensional Hopf algebras over Dedeknind domain. This construction is based on the Hennings invariant of 3-manifolds and Drinfeld's quantum double. We will show that the WRT SO(3) invariant is equivalent to the Hennings invariant associated to U_q(sl₂) when restricted to rational homology spheres. We will also indicate why the Hennings invariant is more suitable for studying Ohtsuki's perturbative expasion.
Coauthors: T. Kerler, S. Kuppum, P. Srinivasan

Time

May 15 2008 - 2:30pm - 3:30 pm

Location

MW 154

Speaker

Vladimir Turaev (University of Indiana at Bloomington)

Abstract

We compute the Dijkgraaf-Witten invariants of surfaces in terms of projective representations of groups. As an application we prove that the complex Dijkgraaf-Witten invariants of surfaces of positive genus are positive integers.

Time

Mar 6 2008 - 3:30pm - 4:30 pm

Location

SO 54

Speaker

Oliver Dasbach (Louisiana State University)

Abstract

We will discuss a dimer model for the Alexander polynomial - essentially due to Kauffman - and its relations to other knot invariants.

Time

Feb 28 2008 - 3:30pm - 4:30 pm

Location

SO 54

Speaker

Iain Moffatt (University of Waterloo)

Abstract

In this talk I will give an overview of various connections between the Tutte polynomial and its generalizations and polynomial invariants of knots. I will begin by reviewing well known relations between the Tutte polynomial of a plane graph and the Jones and HOMFLY polynomials of a knot. I will then go on to discuss several ways Bollobas and Riordan's recently defined ribbon graph polynomial (which was motivated by very different knot theoretical considerations) has been used to extend these results. Finally I will outline connections between the graph polynomials and Khovanov homology.

Time

Feb 14 2008 - 3:30pm - 4:30 pm

Location

SO 54

Speaker

Atabey Kaygun (The Ohio State University)

Abstract

Linear Crossed-Simplicial Groups and Leibniz (Co)Homology

Time

Nov 15 2007 - 1:30pm

Location

DL 357 (Dreese Lab)

Speaker

Mikhail Khovanov (Columbia University)

Seminar Website

http://www.math.ohio-state.edu/~kerler/LoDAT.php

Abstract

The talk will center on constructing actions of the braid group on triangulated categories and how these actions extend to representations of the category of braid cobordisms.