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arXiv math/0701885math.AG
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锥连通流形

Conic-connected Manifolds

Paltin Ionescu, Francesco Russo

摘要:

我们研究一类特殊的有理连通流形,$X\subset \p^N$,使得两个一般点$x,x' \in X$可以通过包含在$X$中的二次曲线连接。我们证明了这些流形是Fano流形,且具有$b_2\leq 2$ .此外,对$b_2=2$进行了精确的分类。关于其多阶的高维完全相交提供了$b_2=1$情形的例子。分类结果的证明使用了合理性的一般表征,在合适的覆盖家庭的有理曲线。

英文摘要:

We study a particular class of rationally connected manifolds, $X\subset \p^N$, such that two general points $x,x' \in X$ may be joined by a conic contained in $X$. We prove that these manifolds are Fano, with $b_2\leq 2$. Moreover, a precise classification is obtained for $b_2=2$. Complete intersections of high dimension with respect to their multi-degree provide examples for the case $b_2=1$. The proof of the classification result uses a general characterization of rationality, in terms of suitable covering families of rational curves.

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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