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Feb 2, 2013 at 21:47 comment added Ben Wieland I doubt that this is true for some ring of integers in a number field, where Bertini's theorem fails. But you're happy to exclude this case.
Feb 2, 2013 at 9:51 answer added user19475 timeline score: 1
Nov 22, 2012 at 14:22 history bounty ended CommunityBot
Nov 19, 2012 at 20:20 comment added Matthieu Romagny Liu, good point! Of course Poonen's Bertini theorems involve sections with hypersurfaces of large degree. I thought that in the classical proof that abelian varieties are quotients of jacobians, it was important to cut by hyperplanes. Now that I think about it again, I see that it is not.
Nov 19, 2012 at 15:24 history edited user19475 CC BY-SA 3.0
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Nov 15, 2012 at 21:17 comment added Qing Liu @Timo: the statement should hold over local (maybe noetherian) rings because Bertini's theorem is true in this case.
Nov 15, 2012 at 21:15 comment added Qing Liu @Matthieu: it is true over finite fields. The proof, as in the classical case, relies on Bertini's theorem over finite fields and it is proved by Gabber and by Poonen's around 2000.
Nov 15, 2012 at 17:10 comment added Matthieu Romagny As far as I see from the literature, the question is not settled already if $X$ is the spectrum of a finite field.
Nov 15, 2012 at 16:12 comment added Laurent Moret-Bailly Does your definition of abelian schemes include "projective over $X$"? This at least is necessary. (I assume that by "curve" you mean "smooth proper curve").
Nov 15, 2012 at 15:02 comment added user19475 and jmilne.org/math/CourseNotes/AV.pdf p. 116.
Nov 15, 2012 at 15:01 comment added user19475 See also modular.math.washington.edu/edu/Fall2003/252/lectures/10-17-03/…
Nov 15, 2012 at 15:00 comment added user19475 Yes, I know this, but what I really need is Abelian schemes.
Nov 15, 2012 at 14:35 comment added user25309 something related : in "Algebraic Groups and Class Fields" (J.P Serre), it is proved (VII.13) that on a algebraically closed field, every abelian variety is isomorphic to the quotient of a product of jacobians (of curves) by a connected subgroup.
Nov 15, 2012 at 14:17 history bounty started CommunityBot
Jan 16, 2012 at 20:30 history edited user19475 CC BY-SA 3.0
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