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arXiv math/9912070math.AG
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有理正态曲线模空间的紧化

On a compactification of the moduli space of the rational normal curves

Paolo Cascini

摘要:

对于任何奇数$n$,我们描述了一个光滑的极小(即通过添加一个不可约的超曲面)紧化$\tilde S_n$的拟投射齐次簇$S_{n}=PGL(n+1)/SL(2)$参数化的合理正态曲线在$P^n$。证明了$\tilde S_{n}$同构于秩为$n$和陈多项式$(1+t)^{n+2}$的$P^n$上半稳定层的Maruyama格式的一个分量,并计算了它的贝蒂数.特别地,$\tilde S_{3}$同构于G.埃林斯格鲁德河Piene和S. Strømme(空间曲线,Proc. Conf.,LNM 1266)。

英文摘要:

For any odd $n$, we describe a smooth minimal (i.e. obtained by adding an irreducible hypersurface) compactification $\tilde S_n$ of the quasi-projective homogeneous variety $S_{n}=PGL(n+1)/SL(2)$ that parameterizes the rational normal curves in $P^n$. We show that $\tilde S_{n}$ is isomorphic to a component of the Maruyama scheme of the semi-stable sheaves on $P^n$ of rank $n$ and Chern polynomial $(1+t)^{n+2}$ and we compute its Betti numbers. In particular $\tilde S_{3}$ is isomorphic to the variety of nets of quadrics defining twisted cubics, studied by G. Ellinsgrud, R. Piene and S. Strømme (Space curves, Proc. Conf., LNM 1266).

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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