Timeline for Projective variety with no syzygies but not isomorphic to projective space
Current License: CC BY-SA 2.5
7 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Nov 6, 2010 at 23:48 | comment | added | Sándor Kovács | @Torsten: an example (I think) with a not-basepoint-free system is below. | |
| Nov 6, 2010 at 23:47 | comment | added | Sándor Kovács | @Colin: here is why this is not surprising: The section ring of $\mathcal L$, $R=\oplus_n H^0(X,\mathcal L^n)$ describes $Y={\rm Proj}R$ and not $X$. Your condition simply means that the rational map given by some high power of $\mathcal L$ maps onto a projective space. Exactly as in Torsten's example. | |
| Nov 6, 2010 at 18:54 | comment | added | Sándor Kovács | @Torsten: thanks for the clarification. I was sure it had to be something different. :) This is a good question. Maybe you should pose it as a question. | |
| Nov 6, 2010 at 16:08 | history | edited | Torsten Ekedahl | CC BY-SA 2.5 |
added 272 characters in body
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| Nov 6, 2010 at 13:58 | comment | added | user2529 | your answer is unexpected and surprising! (not to say the least, very helpful). Thanks! | |
| Nov 6, 2010 at 13:50 | vote | accept | CommunityBot | ||
| Nov 6, 2010 at 10:44 | history | answered | Torsten Ekedahl | CC BY-SA 2.5 |