A local-global principle for polyquadratic twists of abelian surfaces
Abstract
We say that two abelian varieties and defined over a field are polyquadratic twists if they are isogenous over a Galois extension of whose Galois group has exponent dividing . Let and be abelian varieties defined over a number field of dimension . In this article we prove that, if , then and are polyquadratic twists if and only if for almost all primes of their reductions modulo are polyquadratic twists. We exhibit a counterexample to this local-global principle for . This work builds on a geometric analogue by Khare and Larsen, and on a similar criterion for quadratic twists established by Fit\'e, relying itself on the works by Rajan and Ramakrishnan.
Keywords
Cite
@article{arxiv.2210.06317,
title = {A local-global principle for polyquadratic twists of abelian surfaces},
author = {Francesc Fité and Antonella Perucca},
journal= {arXiv preprint arXiv:2210.06317},
year = {2024}
}
Comments
17 pages. To appear in Indiana University Mathematics Journal. Mild expository changes