A local-global principle for polyquadratic twists of abelian surfaces

Fuente: arXiv
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Hauptverfasser: Fité, Francesc, Perucca, Antonella
Format: Preprint
Veröffentlicht: 2022
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author Fité, Francesc
Perucca, Antonella
author_facet Fité, Francesc
Perucca, Antonella
contents We say that two abelian varieties $A$ and $A'$ defined over a field $F$ are polyquadratic twists if they are isogenous over a Galois extension of $F$ whose Galois group has exponent dividing $2$. Let $A$ and $A'$ be abelian varieties defined over a number field $K$ of dimension $g\geq 1$. In this article we prove that, if $g\leq 2$, then $A$ and $A'$ are polyquadratic twists if and only if for almost all primes $\p$ of $K$ their reductions modulo $\p$ are polyquadratic twists. We exhibit a counterexample to this local-global principle for $g=3$. This work builds on a geometric analogue by Khare and Larsen, and on a similar criterion for quadratic twists established by Fité, relying itself on the works by Rajan and Ramakrishnan.
format Preprint
id arxiv_https___arxiv_org_abs_2210_06317
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle A local-global principle for polyquadratic twists of abelian surfaces
Fité, Francesc
Perucca, Antonella
Number Theory
11G10, 11G35
We say that two abelian varieties $A$ and $A'$ defined over a field $F$ are polyquadratic twists if they are isogenous over a Galois extension of $F$ whose Galois group has exponent dividing $2$. Let $A$ and $A'$ be abelian varieties defined over a number field $K$ of dimension $g\geq 1$. In this article we prove that, if $g\leq 2$, then $A$ and $A'$ are polyquadratic twists if and only if for almost all primes $\p$ of $K$ their reductions modulo $\p$ are polyquadratic twists. We exhibit a counterexample to this local-global principle for $g=3$. This work builds on a geometric analogue by Khare and Larsen, and on a similar criterion for quadratic twists established by Fité, relying itself on the works by Rajan and Ramakrishnan.
title A local-global principle for polyquadratic twists of abelian surfaces
topic Number Theory
11G10, 11G35
url https://arxiv.org/abs/2210.06317