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arXiv · 2308.15297

The geometry and arithmetic of bielliptic Picard curves

Jef Laga·Ari Shnidman
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Abstract

We study the geometry and arithmetic of the curves $C \colon y^3 = x^4 + ax^2 + b$ and their associated Prym abelian surfaces $P$. We prove a Torelli theorem in this context and give a geometric proof of the fact that $P$ has quaternionic multiplication (QM) by the quaternion order of discriminant $6$. This allows us to describe the Galois action on the geometric endomorphism algebra of $P$. As an application, we classify the torsion subgroups of the Mordell-Weil groups $P(\mathbb{Q})$, as both abelian groups and $\text{End}(P)$-modules.

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Jef Laga, Ari Shnidman. 2023-08-29. The geometry and arithmetic of bielliptic Picard curves. https://arxiv.org/abs/2308.15297

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