Disproof of modularity of moduli space of CY 3-folds of double covers of P3 ramified along eight planes in general positions

Ralf Gerkmann; Sheng Mao; Kang Zuo

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arXiv · 0709.1051

Disproof of modularity of moduli space of CY 3-folds of double covers of P3 ramified along eight planes in general positions

Ralf Gerkmann·Sheng Mao·Kang Zuo

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Abstract

We prove that the moduli space of Calabi-Yau 3-folds coming from eight planes of $P^3$ in general positions is not modular. In fact we show the stronger statement that the Zariski closure of the monodromy group is actually the whole $Sp(20,R)$. We construct an interesting submoduli, which we call \emph{hyperelliptic locus}, over which the weight 3 $Q$-Hodge structure is the third wedge product of the weight 1 $Q$-Hodge structure on the corresponding hyperelliptic curve. The non-extendibility of the hyperelliptic locus inside the moduli space of a genuine Shimura subvariety is proved.

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BibTeX RIS

Ralf Gerkmann, Sheng Mao, Kang Zuo. 2007-09-07. Disproof of modularity of moduli space of CY 3-folds of double covers of P3 ramified along eight planes in general positions. https://arxiv.org/abs/0709.1051

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