Skip to main content
10 events
when toggle format what by license comment
Apr 13, 2017 at 12:58 history edited CommunityBot
replaced http://mathoverflow.net/ with https://mathoverflow.net/
Jan 5, 2012 at 10:37 answer added Remke Kloosterman timeline score: 3
Jan 4, 2012 at 15:51 comment added naf There is indeed a notion of isogeny for K3 surfaces; see the paper of Mukai "On the moduli space of bundles on a K3 surface I" and the preprint "Fourier-Mukai partners of K3 surfaces in positive characteristic" by Lieblich and Olsson (arxiv.org/abs/1112.5114)
Jan 4, 2012 at 15:38 comment added naf If $k$ is finite then $Pic(X)$ is expected to have rank at least two. It's not clear, at least to me, what to expect in this case.
Jan 4, 2012 at 14:42 comment added Keerthi Madapusi Are things different for finite fields? I don't want to use the Tate conjecture.
Jan 4, 2012 at 7:36 comment added naf @Keerthi: Are you assuming that $k$ is a finite field or is it just assumed to be of characteristic $>2$?
Jan 3, 2012 at 21:06 vote accept Keerthi Madapusi
Jan 3, 2012 at 21:06
Jan 3, 2012 at 20:08 answer added Donu Arapura timeline score: 10
Jan 3, 2012 at 19:48 comment added Donu Arapura I haven't thought this through carefully (my new years resolution is to limit mathoverflow activity), but suppose $k=\bar k$ and you took a general point $(X,\lambda)$ in the moduli space of polarized K3's with $\lambda^2=2p$. I suspect that you should be able to argue that $\lambda$ generates $Pic(X)$, so you would have counterexample.
Jan 3, 2012 at 18:03 history asked Keerthi Madapusi CC BY-SA 3.0