### This Week’s Finds in Mathematical Physics (Week 245)

#### Posted by John Baez

In week245 of This Week’s Finds, read about the Fields Institute workshop on Higher Categories and Their Applications — and the piano Coxeter played at the age of three!

Posted at February 12, 2007 2:29 AM UTC

## Re: This Week’s Finds in Mathematical Physics (Week 245)

But to be fair, there’s another possibility intermediate between Gray and Weak2Cat:

Toby = [strict 2-categories, weak 2-functors, weak natural transformations, modifications]

Except nobody is ever going to talk about the 3category Toby, because it

isequivalent to Weak2Cat!And that’s why everybody kept citing some comment of Bénabou’s, to the effect that the really important thing was not weak 2categories (which he invented) but weak 2functors (which I guess he also invented at the same time, at least in full generality).