## Categorification, Trace Groups, Matrix Factorizations and a Question Nantel
Quickly Solved

(see
here for more details... the transparencies will be available)

### Dror Bar-Natan (U. of T.)

Recently I emailed Nantel a short applied algebra question (asked jointly
with Dylan Thurston), and he (along with Christophe Hohlweg) quickly solved
it. In return, I have to explain why is it interesting.

After quickly stating the question I'll tell you about categorification
(a bold suggestion of I. Frenkel, that much of math is the Euler characteristic
of some "higher math", much like much of algebra is q-algebra at q=1). I'll
then define traces and trace groups, which allow Euler characteristics to
take values in objects more interesting than merely numbers. Finally I'll
introduce the category of matrix factorizations, which is the core of a surpising
new method for constructing homological theories from local data.

The ideas to be introduced in my talk (categorifcation, trace groups and
matrix factorizations) are all conceptual and foundational and worthy of your
time, definitely more than the incomplete (though possibly valid) logic that
lead us to our question to Nantel. So assuming some luck, I'll only have
time to tell the latter part of the story over coffee after my talk. I hope
there's good coffee up there north of 401.

Applied Algebra seminar home