Modular tensor categories

Depending on who comes, we may continue talking for a little while about the "group of fractions" approach to the Thompson group. I have an idea for constructing Thompson group analogues of higher dimensional diffeomorphism groups, but it's not quite all there.

Our main activity will be to learn the definition and some examples of modular tensor categories, with a view towards understanding their role in topological field theory. (Perhaps in later weeks we can discuss a new plan I have for classifying small examples of modular tensor categories.)