Timeline for Duals of Abelian Categories
Current License: CC BY-SA 2.5
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 13, 2017 at 12:58 | history | edited | CommunityBot |
replaced http://mathoverflow.net/ with https://mathoverflow.net/
|
|
| Sep 24, 2010 at 16:52 | comment | added | Martin Brandenburg | Ah ok. This is an example of a morphism in the category of loc. comp. top. groups, which is mono and epi, but not iso. Thus this category is not abelian, as I expected. | |
| Sep 24, 2010 at 16:42 | comment | added | Todd Trimble | The homomorphism R --> R/Z x R/Z which takes t to (t mod Z, st mod Z) where s is irrational. This is a continuous injective homomorphism, with dense image. | |
| Sep 24, 2010 at 15:03 | comment | added | Martin Brandenburg | @Todd: Hm, I don't understand this example yet. Which homomorphism are you considering? And also, is it continuous? | |
| Sep 24, 2010 at 14:11 | comment | added | Todd Trimble | Since the category of locally compact Hausdorff abelian groups is self-dual, we may as well ask whether every monomorphism is a kernel. And indeed that's false: kernels are closed subgroups, so the irrational line on a torus would be a counterexample. | |
| Sep 23, 2010 at 9:23 | history | edited | Martin Brandenburg | CC BY-SA 2.5 |
added 239 characters in body
|
| Sep 23, 2010 at 9:17 | history | answered | Martin Brandenburg | CC BY-SA 2.5 |