Timeline for There are no abstract categories
Current License: CC BY-SA 4.0
12 events
| when toggle format | what | by | license | comment | |
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| Oct 10, 2022 at 12:18 | comment | added | David Roberts♦ | @Alec I used your ResearchGate email, I hope that's current. If not, my nLab page will get you mine. | |
| Oct 10, 2022 at 10:31 | comment | added | Alec Rhea | @DavidRoberts Much appreciated. | |
| Oct 10, 2022 at 5:21 | comment | added | David Roberts♦ | @AlecRhea oh, that's funny :-) I'll send you an email with more details about the newer work. | |
| Oct 10, 2022 at 4:20 | comment | added | Trebor | This IMO shows that the definition of concreteness as a property is reduced to a constraint on the size of the category, and therefore is not the correct notion. A concrete categorie should be a category equipped with a faithful functor to Set, i.e. it is a structure instead of a property. | |
| Oct 10, 2022 at 3:50 | comment | added | Alec Rhea | @DavidRoberts Found it! (and it looks like I actually introduced you to the result originally; small world heh) | |
| Oct 10, 2022 at 3:21 | comment | added | Alec Rhea | @DavidRoberts Very (!!!) cool! I think you and I actually had an exchange on here about that original result a few years back, I’d be very interested to hear more about the developments you’ve been collaborating on. | |
| Oct 10, 2022 at 3:19 | vote | accept | Alec Rhea | ||
| Oct 10, 2022 at 3:15 | comment | added | David Roberts♦ | In fact even more is true than Simon's answer: every locally small category is a quotient (by a congruence on its hom-sets, much like the classical homotopy category) of a concrete category. This was a result of Kučera in NBG (incl global choice), but Martti Karvonen and I have reduced it to work in Algebraic Set Theory with EM (no preprint yet, but I've given talks about it) | |
| Oct 9, 2022 at 23:09 | history | became hot network question | |||
| Oct 9, 2022 at 17:26 | history | edited | LSpice | CC BY-SA 4.0 |
TeX; name of "appropriate foundation"
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| Oct 9, 2022 at 15:28 | answer | added | Simon Henry | timeline score: 21 | |
| Oct 9, 2022 at 15:01 | history | asked | Alec Rhea | CC BY-SA 4.0 |