Re: Codensity and the ultrafilter monad

Tom Leinster <Tom.Leinster@glasgow.ac.uk> wrote, in part:

The codensity monad of the inclusion FinSet --> Set is the ultrafilter monad. This seems a rather basic fact, but I've been unable to find it in the literature. I'd be grateful if someone could tell me a reference.

I can't be certain, but I can easily imagine Oswald Wyler or Ernie Manes having noticed that fact in the dim, dark, distant past. Perhaps Ernie will chime in :-) . HTH. Cheers, -- Fred [For admin and other information see: http://www.mta.ca/~cat-dist/ ]