Timeline for Is every monomorphism of commutative Hopf algebras (over a field) injective?
Current License: CC BY-SA 2.5
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Feb 5, 2010 at 6:07 | comment | added | Anton Geraschenko | X=50 (see mathoverflow.net/faq#reputation) | |
| Feb 5, 2010 at 5:54 | comment | added | Mariano Suárez-Álvarez | Nicolás, you need X reputation points for some X > 1 to comment on other people's answers. There are two accounts (mathoverflow.net/users/3679/nicolas-schmidt and mathoverflow.net/users/3693/nicolas-schmidt) under your name. I'll ask on meta for them to be joined. | |
| Feb 3, 2010 at 14:09 | comment | added | Nicolas Schmidt | For some reason I cannot comment on his answer, I can only add comments to my own (?). | |
| Feb 3, 2010 at 12:05 | comment | added | David Jordan | By the way, Ben won't see your further questions unless you comment to his answer. | |
| Feb 3, 2010 at 12:04 | comment | added | David Jordan | Nicolas, yes you are right. I misunderstood Ben's answer and the comment following it. I have deleted my incorrect "contribution" to the conversation. So the answer to your question, combining Ben's first sentence, with Mariano's answer is, in fact, yes? | |
| Feb 3, 2010 at 11:45 | comment | added | Nicolas Schmidt | The example of Ben cannot be correct, if I understand him correctly: The category of finite groups is embedded as a full subcategory of the category of affine group schemes over k via the constant group functor. Any epimorphism in the surrounding category remains of course an epimorphism in the smaller one. If the inclusion of a transposition into $S_3$ were an epimorphism of algebraic groups, it be so as abstract groups. But as was already mentioned, every epimorphism of finite groups is surjective (in fact this statement remains true without 'finite' and is an exercise in Saunders MacLane). | |
| Feb 1, 2010 at 9:44 | history | answered | Nicolas Schmidt | CC BY-SA 2.5 |