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On classification of Q-Fano 3-folds with Gorenstein index 2 and Fano index 1/2

Hiromichi Takagi
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Abstract

We obtain a classification of a Q-factorial Q-Fano 3-fold $X$ with the following properties: the Picard number of $X$ is 1; the Gorenstein index of $X$ is 2; the Fano index of $X$ is 1/2; $h^0 (-K_X) \geq 4$; there exists an index 2 point $P$ such that $(X,P)\simeq (\{xy +f(z^2,u)=0\} / \Bbb Z_2 (1,1,1,0), o)$ with $ord f(Z,U)=1$.

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Hiromichi Takagi. 1999-05-12. On classification of Q-Fano 3-folds with Gorenstein index 2 and Fano index 1/2. https://arxiv.org/abs/math/9905068

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