Timeline for Is the category of affine fppf groups closed under normal quotients?
Current License: CC BY-SA 3.0
4 events
| when toggle format | what | by | license | comment | |
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| Jun 7, 2011 at 6:00 | comment | added | Angelo | Matthieu, you are absolutely right. You should probably post your comment as an answer. | |
| Jun 7, 2011 at 5:59 | history | edited | Angelo | CC BY-SA 3.0 |
added 69 characters in body
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| Jun 6, 2011 at 20:35 | comment | added | Matthieu Romagny | Angelo, you seem to assume that $S$ is the spectrum of a field but Daniel is asking about what's happening over a general $S$. In that case, as you certainly know, the quotient $G/N$ is not representable in general (hence not affine). For a counter-example of Raynaud with $S=\mathbb{A}^2_k$, $G=(\mathbb{G}_{a,S})^2$ and $N$ etale over $S$, see Lemma X.14 in Faisceaux amples sur les schemas en groupes et les espaces homogenes. | |
| Jun 6, 2011 at 19:30 | history | answered | Angelo | CC BY-SA 3.0 |