Re: Category without objects

The definition can be found in several well-known textbooks: for example, on page 5 of Freyd's "Abelian Categories" and on page 9 of Mac lane's "Categories for the Working Mathematician". Peter Johnstone On Thu, 5 Mar 2015, Uwe Egbert Wolter wrote:

Some years ago (around 30?) I read a book where it was mentioned that one could define categories without (explicit) objects in the sense that objects are mimicked by identity morphisms. Unfortunately, I can not reconstruct what book it was.

I know how this works. I would, however, like to have a reference.

Best

Uwe Wolter

[For admin and other information see: http://www.mta.ca/~cat-dist/ ]