Timeline for Is each rationally chain connected surface rational?
Current License: CC BY-SA 3.0
6 events
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Sep 4, 2014 at 6:10 | vote | accept | Mikhail Skopenkov | ||
Sep 3, 2014 at 21:55 | comment | added | Roberto Pignatelli | I edited my post explaining this point, I hope is ok now. Really, i thik you could avoid solving the indeterminacy, as this is just a finite set (see Beauville's proof of Proposition III.20). Anyway, I solved them to be safe: then you pull-back holomorphic forms, and this gives the injective map we need. | |
Sep 3, 2014 at 21:50 | history | edited | Roberto Pignatelli | CC BY-SA 3.0 |
Explained the implication "uniruled implies vanishing plurigenera"
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Sep 3, 2014 at 17:31 | comment | added | Mikhail Skopenkov | Thank you very much, this completes the proof. Indeed, once all plurigenera vanish, the surface is ruled by the Enriques theorem [2,Theorem VI.17]. However, the assertion ``if a surface S is uniruled, all plurigenera vanish'' requires some work for the proof. E.g., we cannot just take a pullback of a pluricanonical section because the dominant map $X\times \mathbb{P}^1\to S$ may not be defined everywhere. Thus we need to start with eliminating indeterminacy using [2,Theorem II.7] and so on. That is why a reference to the assertions is preferable. | |
Sep 3, 2014 at 15:20 | history | edited | Roberto Pignatelli | CC BY-SA 3.0 |
misprints corrected, removed some useless sentence
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Sep 3, 2014 at 13:07 | history | answered | Roberto Pignatelli | CC BY-SA 3.0 |