Timeline for In which categories is the union of subobjects given by the pushout over the intersection?
Current License: CC BY-SA 4.0
7 events
| when toggle format | what | by | license | comment | |
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| Dec 25, 2022 at 1:56 | comment | added | Kevin Carlson | @PaulTaylor The only result there on which categories have these "effective unions" seems to be 2.1, which is only for extensive categories, right? Really interesting paper, though! | |
| Dec 24, 2022 at 22:11 | comment | added | Paul Taylor | Dowloadable book, not sure if it's legit. Vengo a Buenos Aires 5 de enero, donde encontraré Claudio Hermida. | |
| Dec 24, 2022 at 21:44 | comment | added | godelian | @PaulTaylor I don't have Reyes' paper at hand, but I reproduced the proof in my master thesis, page 13 Lemma 3.2.12 at cms.dm.uba.ar/Members/cespindo/tesis.pdf (there's a change of terminology though, but the category is coherent). | |
| Dec 24, 2022 at 21:38 | comment | added | Paul Taylor | @TimCampion: Barr's paper is applicable to Abelian categories as well as pretoposes. | |
| Dec 24, 2022 at 21:36 | comment | added | Paul Taylor | That's a long paper by Reyes, on many topics. Where in it is this particular result? | |
| Dec 24, 2022 at 21:04 | comment | added | Tim Campion | Thanks! I'll hold off on accepting for now -- I'd really like a condition which includes the abelian case as well. | |
| Dec 24, 2022 at 20:25 | history | answered | godelian | CC BY-SA 4.0 |