arXiv 0908.45022009-08math.AG

Seshadri constants on rational surfaces with anticanonical pencils

Taro Sano

备注：: 22 pages. To appear in JPAA

英文摘要：

We study a Seshadri constant at a general point on a rational surface whose anticanonical linear system contains a pencil. First, we describe a Seshadri constant of an ample line bundle on such a rational surface explicitly by the numerical data of the ample line bundle. Secondly, we classify log del Pezzo surfaces which are special in terms of the Seshadri constants of the anticanonical divisors when the anticanonical degree is between 4 and 9.

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