Recovering p-adic valuations from pro-p Galois groups

Let (Formula presented.) be a field with (Formula presented.), where (Formula presented.) denotes the maximal pro-2 quotient of the absolute Galois group of a field (Formula presented.). We prove that then (Formula presented.) admits a (non-trivial) valuation (Formula presented.) which is 2-henselia...

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Main Authors: Koenigsmann, J, Strommen, K
Format: Journal article
Language:English
Published: Wiley 2024
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author Koenigsmann, J
Strommen, K
author_facet Koenigsmann, J
Strommen, K
author_sort Koenigsmann, J
collection OXFORD
description Let (Formula presented.) be a field with (Formula presented.), where (Formula presented.) denotes the maximal pro-2 quotient of the absolute Galois group of a field (Formula presented.). We prove that then (Formula presented.) admits a (non-trivial) valuation (Formula presented.) which is 2-henselian and has residue field (Formula presented.). Furthermore, (Formula presented.) is a minimal positive element in the value group (Formula presented.) and (Formula presented.). This forms the first positive result on a more general conjecture about recovering (Formula presented.) -adic valuations from pro- (Formula presented.) Galois groups which we formulate precisely. As an application, we show how this result can be used to easily obtain number-theoretic information, by giving an independent proof of a strong version of the birational section conjecture for smooth, complete curves (Formula presented.) over (Formula presented.), as well as an analogue for varieties.
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spelling oxford-uuid:5abb8998-484e-4ef8-a9b1-a8d3794d4f392024-08-21T16:19:26ZRecovering p-adic valuations from pro-p Galois groupsJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:5abb8998-484e-4ef8-a9b1-a8d3794d4f39EnglishSymplectic ElementsWiley2024Koenigsmann, JStrommen, KLet (Formula presented.) be a field with (Formula presented.), where (Formula presented.) denotes the maximal pro-2 quotient of the absolute Galois group of a field (Formula presented.). We prove that then (Formula presented.) admits a (non-trivial) valuation (Formula presented.) which is 2-henselian and has residue field (Formula presented.). Furthermore, (Formula presented.) is a minimal positive element in the value group (Formula presented.) and (Formula presented.). This forms the first positive result on a more general conjecture about recovering (Formula presented.) -adic valuations from pro- (Formula presented.) Galois groups which we formulate precisely. As an application, we show how this result can be used to easily obtain number-theoretic information, by giving an independent proof of a strong version of the birational section conjecture for smooth, complete curves (Formula presented.) over (Formula presented.), as well as an analogue for varieties.
spellingShingle Koenigsmann, J
Strommen, K
Recovering p-adic valuations from pro-p Galois groups
title Recovering p-adic valuations from pro-p Galois groups
title_full Recovering p-adic valuations from pro-p Galois groups
title_fullStr Recovering p-adic valuations from pro-p Galois groups
title_full_unstemmed Recovering p-adic valuations from pro-p Galois groups
title_short Recovering p-adic valuations from pro-p Galois groups
title_sort recovering p adic valuations from pro p galois groups
work_keys_str_mv AT koenigsmannj recoveringpadicvaluationsfrompropgaloisgroups
AT strommenk recoveringpadicvaluationsfrompropgaloisgroups