Timeline for Duals of Abelian Categories
Current License: CC BY-SA 2.5
2 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Sep 23, 2010 at 16:17 | comment | added | Theo Johnson-Freyd | This just shows how little I understand compact abelian groups. One of the main things that prevents $(R\text{-mod})^\text{op}$ from being a category of representations is that the canonical map $\coprod^\infty M \to \prod^\infty M$ in $(R\text{-mod})^\text{op}$ is an epi that is not a mono. So if I take the circle, say, and look at its countable, say, coproduct in the category of compact abelian groups --- I don't actually know what I get! But you're telling me that it <strike>surjects</strike>epimorphs onto the countable product? | |
| Sep 23, 2010 at 9:29 | history | answered | Angelo | CC BY-SA 2.5 |