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On factoriality of nodal threefolds

Ivan Cheltsov
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Abstract

We prove the $\mathbb{Q}$-factoriality of a nodal hypersurface in $\mathbb{P}^{4}$ of degree $n$ with at most ${\frac{(n-1)^{2}}{4}}$ nodes and the $\mathbb{Q}$-factoriality of a double cover of $\mathbb{P}^{3}$ branched over a nodal surface of degree $2r$ with at most ${\frac{(2r-1)r}{3}}$ nodes.

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Ivan Cheltsov. 2004-10-18. On factoriality of nodal threefolds. https://arxiv.org/abs/math/0405221

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