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Approximation forte pour les variétés avec une action d’un groupe linéaire

Part of: Arithmetic algebraic geometry Linear algebraic groups and related topics Arithmetic problems. Diophantine geometry

Published online by Cambridge University Press:  08 March 2018

Yang Cao
Yang Cao*
Affiliation:
Max Planck Institute for Mathematics, Vivatsgasse 7, 53111 Bonn, Germany email [email protected], [email protected]
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Abstract

Let $G$ be a connected linear algebraic group over a number field $k$. Let $U{\hookrightarrow}X$ be a $G$-equivariant open embedding of a $G$-homogeneous space $U$ with connected stabilizers into a smooth $G$-variety $X$. We prove that $X$ satisfies strong approximation with Brauer–Manin condition off a set $S$ of places of $k$ under either of the following hypotheses:

  1. (i) $S$ is the set of archimedean places;

  2. (ii) $S$ is a non-empty finite set and $\bar{k}^{\times }=\bar{k}[X]^{\times }$.

The proof builds upon the case $X=U$, which has been the object of several works.

Soit $G$ un groupe linéaire connexe sur un corps de nombres $k$. Soit $U{\hookrightarrow}X$ une inclusion $G$-équivariante d’un $G$-espace homogène $U$ à stabilisateurs connexes dans une $G$-variété lisse $X$. On montre que $X$ satisfait l’approximation forte avec condition de Brauer–Manin hors d’un ensemble $S$ de places de $k$ dans chacun des cas suivants :(i)

(i) $S$ est l’ensemble des places archimédiennes ;

(ii)

(ii) $S$ est un ensemble fini non vide quelconque, et $\bar{k}^{\times }=\bar{k}[X]^{\times }$.

La démonstration utilise le cas $X=U$, qui a fait l’objet de divers travaux.

Keywords

approximation fortecohomologie étaleobstruction de Brauer–Maninespace homogène

MSC classification

Primary: 11G35: Varieties over global fields 14G05: Rational points 14G25: Global ground fields 20G35: Linear algebraic groups over adèles and other rings and schemes
Type
Research Article
Information
Compositio Mathematica , Volume 154 , Issue 4 , April 2018 , pp. 773 - 819
Copyright
© The Author 2018 

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