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arXiv 0811.3522math.AG
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曲面上层模格式的翻转与变分

Flips and variation of moduli schemes of sheaves on a surface

Kimiko Yamada

摘要:

设$H$是非奇异射影曲面$X$上的一个样本线丛,$M(H)$是$X$上秩为2的固定Chern类$H$ -半稳定层的粗模格式.我们表明,如果$H$的变化,并通过墙壁得到更接近$K_X$,然后$M(H)$经历自然翻转相对于典范除子。当$X$最小且Kodaira维数为正时,这一翻转序列终止于$M(H_X)$ ; $H_X$是一个充分的线丛,非常靠近$K_X$,以至于$M(H_X)$的典范除子是nef。注意,所谓的撒迪厄斯型翻转在典范除子方面与翻转有些不同。

英文摘要:

Let $H$ be an ample line bundle on a non-singular projective surface $X$, and $M(H)$ the coarse moduli scheme of rank-two $H$-semistable sheaves with fixed Chern classes on $X$. We show that if $H$ changes and passes through walls to get closer to $K_X$, then $M(H)$ undergoes natural flips with respect to canonical divisors. When $X$ is minimal and its Kodaira dimension is positive, this sequence of flips terminates in $M(H_X)$; $H_X$ is an ample line bundle lying so closely to $K_X$ that the canonical divisor of $M(H_X)$ is nef. Remark that so-called Thaddeus-type flips somewhat differ from flips with respect to canonical divisors.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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