Timeline for Requirement that source and target maps are surjective submersions
Current License: CC BY-SA 4.0
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Feb 13, 2019 at 4:59 | vote | accept | Praphulla Koushik | ||
| Feb 13, 2019 at 4:59 | comment | added | Praphulla Koushik | Yes, I see why they are submersion,, first reason I realise why $s,t$ is submersion is to make sure $\mathcal{G}_1\times_{\mathcal{G}_0}\mathcal{G}_1$ is a manifold (pullback is a manifold if one of the maps is submersions) so that you can talk about multiplication/composition map being smooth... after this also many times I used source/target map are submersions so that pullback is manifold... I do not know much about Deligne Mumford stacks and all that.. may be some day I will know and this answer might be useful... thanks :) | |
| Feb 13, 2019 at 4:26 | comment | added | David Roberts♦ | Well, I answered a different question, namely why should they be submersions, and that information is worth leaving there. | |
| Feb 13, 2019 at 3:42 | comment | added | Praphulla Koushik | This does not deserve to be a question on MO or question on anywhere... it is not a misconception it is just because of my sleepy feeling... of course I do know that source and target maps are surjective,,, what should I do now?? Should I just delete it ? | |
| Feb 13, 2019 at 3:31 | comment | added | Praphulla Koushik | I was also rechecking the definition in arxiv.org/pdf/math/0203100.pdf and it says it is just submersion :D :D It is already surjective so they just did not mention :P :P | |
| Feb 13, 2019 at 3:27 | comment | added | Praphulla Koushik | Ofcourse they are surjective... Given $a\in \mathcal{G}_0$ I can just take $1_a:a\rightarrow a$ in $\mathcal{G}_0$ that says both $s,t$ are surjective... It was asked 5 hours ago i.e., 4 am for me.. I should have just slept off.. My mind did not work and I did not realise that then... I now feel like real stupid :D Sorry for wasting your time.. I feel guilty.... | |
| Feb 13, 2019 at 1:35 | history | edited | David Roberts♦ | CC BY-SA 4.0 |
added 252 characters in body
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| Feb 13, 2019 at 1:29 | history | answered | David Roberts♦ | CC BY-SA 4.0 |