Timeline for Freyd-Mitchell's embedding theorem
Current License: CC BY-SA 3.0
11 events
| when toggle format | what | by | license | comment | |
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| Oct 30, 2018 at 22:36 | comment | added | Paul Balmer | @Axel and Martin: I'm afraid neither are true. By Yoneda, y(A)=Hom(A,-) is indeed projective, not injective, in the ambient category of A-modules, but not in L a priori (where epimorphisms are more complicated than pointwise epis, very much as with sheafification). The second part of the argument should use a suitable injective object, in which every y(A) embeds. | |
| Oct 4, 2013 at 13:33 | comment | added | Martin Brandenburg | @Axel: I think you are right. | |
| Feb 12, 2013 at 22:19 | comment | added | Axel Boldt | I think we should define A-Mod to be the category of additive functors from A to Ab, in analogy with the category of modules over a ring. I don't see why the functors Hom(A,-) are injective in the functor category; aren't they projective? | |
| Dec 26, 2012 at 16:45 | comment | added | Theo Buehler | @Axel: thanks again, I finally found the time for doing it. | |
| Dec 26, 2012 at 16:43 | history | edited | Theo Buehler | CC BY-SA 3.0 |
fixed a typo noted by a reader, used markdown instead of abusing MathJax
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| Dec 5, 2012 at 21:43 | comment | added | Theo Buehler | @Axel: Yes, you're right, thanks for catching that typo. There are a few more. I will edit soon. | |
| May 7, 2011 at 2:00 | vote | accept | Bruno Stonek | ||
| Nov 30, 2010 at 12:03 | comment | added | Sheikraisinrollbank | I really like this answer. | |
| Nov 30, 2010 at 10:41 | comment | added | Theo Buehler | Oh sure, somehow I missed to mention this article. It can be found here: archive.numdam.org/article/BSMF_1962__90__323_0.pdf | |
| Nov 30, 2010 at 9:03 | comment | added | Martin Brandenburg | The named properties of $Lex(A,Ab)$ and the embedding of $A$ into it are presented in Gabriel's thesis "Des categories abeliennes". | |
| Nov 30, 2010 at 7:05 | history | answered | Theo Buehler | CC BY-SA 2.5 |