NORTHEASTERN UNIVERSITY
MATHEMATICS DEPARTMENT
 
Geometry-Algebra-Singularities-Combinatorics 
Seminar
 
 
Skein modules and the noncommutative torus 
 
 

Razvan Gelca

(University of Michigan)
 
 

Northeastern University

509 Lake Hall

1:30 p.m., Monday, March 1, 1999

 
 
 
Abstract:  In the 80's, several knot invariants for knots in the 3-dimensional sphere were constructed in a purely combinatorial manner, based on skein relations. Consequently, a study of 3-manifolds in the context of skein modules was initiated, by considering skein relations for knots in arbitrary manifolds. It was noticed that Kauffman bracket skein modules are related to SL(2,C) representations of the fundamental group. In the case when the manifold is a cylinder over a surface, the associated skein module has a natural algebra structure.

The present talk is focused on a joint result with Charles Frohman, in which we show that the Kauffman bracket skein algebra of the cylinder over a torus is canonically isomorphic to the subalgebra of the noncommutative torus spanned by noncommutative cosines. I will describe several applications of this fact to the study of skein modules and to the computation of quantum knot invariants. In particular I will define a noncommutative version of the A-polynomial of a knot, as a finitely generated ideal of polynomials in the quantum plane.  

 
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Web page:  Alexandru I. Suciu  Created: Feb. 5, 1999    Updated: Feb. 5, 1999 
Comments to:  alexsuciu@neu.edu URL: http://www.math.neu.edu/~suciu/gas/gelca.html