Boundedness of the $p$-primary torsion of the Brauer group of an abelian variety

Fuente: arXiv
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Autore principale: D'Addezio, Marco
Natura: Preprint
Pubblicazione: 2022
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author D'Addezio, Marco
author_facet D'Addezio, Marco
contents We prove that the $p^\infty$-torsion of the transcendental Brauer group of an abelian variety over a finitely generated field of characteristic $p>0$ is bounded. This answers a (variant of a) question asked by Skorobogatov and Zarhin for abelian varieties. To do this, we prove a "flat Tate conjecture" for divisors. In the text, we also study other geometric Galois-invariant $p^\infty$-torsion classes of the Brauer group which are not in the transcendental Brauer group. These classes, in contrast with our main theorem, can be infinitely $p$-divisible. We explain how the existence of these $p$-divisible towers is naturally related to the failure of surjectivity of specialisation morphisms of Néron--Severi groups in characteristic $p$.
format Preprint
id arxiv_https___arxiv_org_abs_2201_07526
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Boundedness of the $p$-primary torsion of the Brauer group of an abelian variety
D'Addezio, Marco
Algebraic Geometry
Number Theory
14F22, 19E15, 14F42, 14C25, 14F30
We prove that the $p^\infty$-torsion of the transcendental Brauer group of an abelian variety over a finitely generated field of characteristic $p>0$ is bounded. This answers a (variant of a) question asked by Skorobogatov and Zarhin for abelian varieties. To do this, we prove a "flat Tate conjecture" for divisors. In the text, we also study other geometric Galois-invariant $p^\infty$-torsion classes of the Brauer group which are not in the transcendental Brauer group. These classes, in contrast with our main theorem, can be infinitely $p$-divisible. We explain how the existence of these $p$-divisible towers is naturally related to the failure of surjectivity of specialisation morphisms of Néron--Severi groups in characteristic $p$.
title Boundedness of the $p$-primary torsion of the Brauer group of an abelian variety
topic Algebraic Geometry
Number Theory
14F22, 19E15, 14F42, 14C25, 14F30
url https://arxiv.org/abs/2201.07526