2 May
2013
2 May
'13
6:46 a.m.
Jean B?nabou wrote in small part:
The one [notion of equivalence of categories] which might serve here is f full and faithful and essentially surjective. But unless we have AC it is not symmetric, even for A and B small.
Then the obvious thing to try is to symmetrise it: An equivalence between A and B is a span A <- X -> B of fully faithful and essentially surjective functors. --Toby [For admin and other information see: http://www.mta.ca/~cat-dist/ ]