Departmental Colloquium

Event Information Computation without Representation
16:00 on Wednesday November 21, 2018
17:00 on Wednesday November 21, 2018
BA6183, Bahen Center, 40 St. George St.
Dror Bar-Natan
http://www.math.toronto.edu/drorbn
University of Toronto
http://www.math.toronto.edu

A major part of "quantum topology" (you don't have to know what's that) is the definition and computation of various knot invariants by carrying out computations in quantum groups (you don't have to know what are these). Traditionally these computations are carried out "in a representation", but this is very slow: one has to use tensor powers of these representations, and the dimensions of powers grow exponentially fast.

In my talk I will describe a direct-participation method for carrying out these computations without having to choose a representation and explain why in many ways the results are better and faster. The two key points we use are a technique for composing infinite-order "perturbed Gaussian" differential operators, and the little-known fact that every semi-simple Lie algebra can be approximated by solvable Lie algebras, where computations are easier.

This is joint work with Roland van der Veen and continues work by Rozansky and Overbay.

http://www.math.toronto.edu/drorbn/Talks/Toronto-1811/