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Wulf-Dieter Geyer, Moshe Jarden, and Aharon Razon
Strong approximation theorem for absolutely integral varieties over PSC Galois extensions of global fields view print
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Published: |
October 19, 2017
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Keywords: |
PAC field, strong approximation theorem, stabilizing element, Picard group |
Subject: |
12E30 |
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Abstract
Let K be a global field,
V a proper subset of the set of all primes of K,
S a finite subset of V,
and \tilde K (resp. Ksep) a fixed algebraic
(resp. separable algebraic) closure of K.
Let Gal(K)=Gal(Ksep/K) be the absolute Galois group of
K.
For each p∈V we choose a Henselian
(respectively, a real or algebraic) closure
Kp of K at p
in \tilde K if
p is nonarchimedean (respectively, archimedean).
Then,
Ktot,S=\capp∈S\capτ∈Gal(K)Kpτ
is the maximal Galois extension of K in Ksep in which
each
p∈S totally splits.
For each p∈V we choose a p-adic absolute
value | |p of Kp and extend it in the unique
possible way to \tilde K.
For σ=(σ1,...,σe)∈Gal(K)e let
Ktot,S[σ] be the maximal Galois extension of
K in Ktot,S fixed by σ1,...,σe.
Then, for almost all σ∈Gal(K)e (with respect to
the Haar
measure), the field Ktot,S[σ]
satisfies the following local-global principle:
Let V
be an absolutely integral affine variety in AKn.
Suppose that for each p∈S there exists
zp∈ Vsimp(Kp)
and for each p∈V\S there exists
zp∈ V(\tilde K)
such that in both cases |zp|p≦1
if p is nonarchimedean and |zp|p<1 if
p is archimedean.
Then, there exists z∈ V(Ktot,S[σ]) such that
for all
p∈V and for all
τ∈Gal(K) we have:
|zτ|p≦1 if p is
archimedean and |zτ|p<1 if p
is nonarchimedean.
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Author information
Wulf-Dieter Geyer:
Department of Mathematics, Universität Erlangen-Nürnberg, Erlangen, Germany
geyer@mi.uni-erlangen.de
Moshe Jarden:
School of Mathematics, Tel Aviv University, Tel Aviv, Israel
jarden@post.tau.ac.il
Aharon Razon:
Elta, Ashdod, Israel
razona@elta.co.il
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