A specialisation theorem for Lang-Néron groups

Fuente: arXiv
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Main Authors: Kahn, Bruno, Liu, Long
Format: Preprint
Published: 2024
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author Kahn, Bruno
Liu, Long
author_facet Kahn, Bruno
Liu, Long
contents We show that, for a polarised smooth projective variety $B \hookrightarrow \mathbb{P}^n_k$ of dimension $\geq 2$ over an infinite field $k$ and an abelian variety $A$ over the function field of $B$, there exists a dense Zariski open set of smooth geometrically connected hyperplane sections $h$ of $B$ such that $A$ has good reduction at $h$ and the specialisation homomorphism of Lang-Néron groups at $h$ is injective (up to a finite $p$-group in positive characteristic $p$). This gives a positive answer to a conjecture of the first author, which is used to deduce a negative definiteness result on his refined height pairing. This also sheds a new light on Néron's specialisation theorem.
format Preprint
id arxiv_https___arxiv_org_abs_2405_06114
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A specialisation theorem for Lang-Néron groups
Kahn, Bruno
Liu, Long
Algebraic Geometry
Number Theory
11G99, 14K99
We show that, for a polarised smooth projective variety $B \hookrightarrow \mathbb{P}^n_k$ of dimension $\geq 2$ over an infinite field $k$ and an abelian variety $A$ over the function field of $B$, there exists a dense Zariski open set of smooth geometrically connected hyperplane sections $h$ of $B$ such that $A$ has good reduction at $h$ and the specialisation homomorphism of Lang-Néron groups at $h$ is injective (up to a finite $p$-group in positive characteristic $p$). This gives a positive answer to a conjecture of the first author, which is used to deduce a negative definiteness result on his refined height pairing. This also sheds a new light on Néron's specialisation theorem.
title A specialisation theorem for Lang-Néron groups
topic Algebraic Geometry
Number Theory
11G99, 14K99
url https://arxiv.org/abs/2405.06114