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arXiv · 1204.6254

On the Göttsche Threshold

Steven L. Kleiman·Vivek V. Shende·with an appendix by Ilya Tyomkin
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Abstract

For a line bundle L on a smooth surface S, it is now known that the degree of the Severi variety of cogenus-d curves is given by a universal polynomial in the Chern classes of L and S if L is d-very ample. For S rational, we relax the latter condition substantially: it suffices that three key loci be of codimension more than d. As corollaries, we prove that the condition conjectured by Göttsche suffices if S is P^2 or S is any Hirzebruch surface, and that a similar condition suffices if S is any classical del Pezzo surface.

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Steven L. Kleiman, Vivek V. Shende, with an appendix by Ilya Tyomkin. 2013-02-06. On the Göttsche Threshold. https://arxiv.org/abs/1204.6254

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