dear colleagues, i am looking for a paper that i remember reading some years ago, but now seem unable to find. it contained a detailed discussion of general quotients of categories, i.e., where objects can get identified. i'd be grateful for any hints anyone can offer. -- thanks, björn [For admin and other information see: http://www.mta.ca/~cat-dist/ ]
General quotient categories have been studied by Charles Ehresmann in the 60's. In particular in his book "Cat?gories et Structures" (Dunod 1965), Chapter III, which takes back results from "Cohomologie ? valeurs dans une cat?gorie dominee" (1964) and other articles which are reprinted in "Charles Ehresmann: Oeuvres completes et commentees" Part III-2, freely downloadable from http://ehres.pagesperso-orange.fr Best Andree [For admin and other information see: http://www.mta.ca/~cat-dist/ ]
Might be this: M.A. Bednarczyk, A.M. Borzyszkowski and W. Pawlowski, Generalized congruences-epimorphisms in Cat, Theory Appl. Categ. 5 (1999), No. 11, 266-280. Regards, Marco On 15/giu/2016, at 19.49, Björn Gohla wrote:
dear colleagues,
i am looking for a paper that i remember reading some years ago, but now seem unable to find.
it contained a detailed discussion of general quotients of categories, i.e., where objects can get identified.
i'd be grateful for any hints anyone can offer.
-- thanks, björn
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
On Thursday 16 June 2016 22:14:36 Marco Grandis wrote:
Might be this: M.A. Bednarczyk, A.M. Borzyszkowski and W. Pawlowski, Generalized congruences-epimorphisms in Cat, Theory Appl. Categ. 5 (1999), No. 11, 266-280. [...]
that's exactly the one. thanks. [For admin and other information see: http://www.mta.ca/~cat-dist/ ]
Hello Björn, Back in the 70s Reinhard Börger wrote a Master's thesis on such general quotient categories. His main findings of the time are recorded as Theorem 2.3 in my commemorative article of his work, available at http://www.math.yorku.ca/~tholen/ReinhardBoergerTribute.pdf A shortened version of that article is due to appear in the "Cahiers". Regards, Walter Quoting Björn Gohla <b.gohla@gmx.de>:
dear colleagues,
i am looking for a paper that i remember reading some years ago, but now seem unable to find.
it contained a detailed discussion of general quotients of categories, i.e., where objects can get identified.
i'd be grateful for any hints anyone can offer.
-- thanks, björn
[For admin and other information see: http://www.mta.ca/~cat-dist/ ]
participants (4)
-
Andrée Ehresman -
Björn Gohla -
Marco Grandis -
tholen＠mathstat.yorku.ca