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arXiv · 1001.4950

Degenerations of triple coverings and Thomae's formula

Keiji Matsumoto·Tomohide Terasoma
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Abstract

In this paper, we prove Thomae's formula for a triple covering of $\bold P^1$ with arbitrary index. This formula gives a relation between theta constants, determinants of period integrals and the difference products of branch points. To specify a symplectic basis of the curve, we use the combinatorics of binary trees on $\bold P^1$. This symplectic basis behaves so well for degenerations that we obtain the absolute constant in this formula and reduce it to a special case treated in [Bershadsky-Radul], [Nakayashiki].

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Keiji Matsumoto, Tomohide Terasoma. 2010-02-02. Degenerations of triple coverings and Thomae's formula. https://arxiv.org/abs/1001.4950

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