When is the étale open topology a field topology?

We investigate the following question: Given a field K, when is the ´etale open topology EK induced by a field topology? On the positive side, when K is the fraction field of a local domain R 6= K, using a weak form of resolution of singularities due to Gabber, we show that EK agrees with the R-adic...

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Detalhes bibliográficos
Principais autores: Dittmann, P, Walsberg, E, Ye, J
Formato: Journal article
Idioma:English
Publicado em: Springer 2023
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author Dittmann, P
Walsberg, E
Ye, J
author_facet Dittmann, P
Walsberg, E
Ye, J
author_sort Dittmann, P
collection OXFORD
description We investigate the following question: Given a field K, when is the ´etale open topology EK induced by a field topology? On the positive side, when K is the fraction field of a local domain R 6= K, using a weak form of resolution of singularities due to Gabber, we show that EK agrees with the R-adic topology when R is quasi-excellent and henselian. Various pathologies appear when dropping the quasi-excellence assumption. For locally bounded field topologies, we introduce the notion of generalized t-henselianity (gthenselianity) following Prestel and Ziegler. We establish the following: For a locally bounded field topology τ, the ´etale open topology is induced by τ if and only if τ is gt-henselian and some non-empty ´etale image is τ-bounded open. On the negative side, we obtain that for a pseudo-algebraically closed field K, EK is never induced by a field topology.
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spelling oxford-uuid:d41f9690-1299-4754-a3f3-c872dd4b40192023-04-25T11:55:37ZWhen is the étale open topology a field topology?Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:d41f9690-1299-4754-a3f3-c872dd4b4019EnglishSymplectic ElementsSpringer2023Dittmann, PWalsberg, EYe, JWe investigate the following question: Given a field K, when is the ´etale open topology EK induced by a field topology? On the positive side, when K is the fraction field of a local domain R 6= K, using a weak form of resolution of singularities due to Gabber, we show that EK agrees with the R-adic topology when R is quasi-excellent and henselian. Various pathologies appear when dropping the quasi-excellence assumption. For locally bounded field topologies, we introduce the notion of generalized t-henselianity (gthenselianity) following Prestel and Ziegler. We establish the following: For a locally bounded field topology τ, the ´etale open topology is induced by τ if and only if τ is gt-henselian and some non-empty ´etale image is τ-bounded open. On the negative side, we obtain that for a pseudo-algebraically closed field K, EK is never induced by a field topology.
spellingShingle Dittmann, P
Walsberg, E
Ye, J
When is the étale open topology a field topology?
title When is the étale open topology a field topology?
title_full When is the étale open topology a field topology?
title_fullStr When is the étale open topology a field topology?
title_full_unstemmed When is the étale open topology a field topology?
title_short When is the étale open topology a field topology?
title_sort when is the etale open topology a field topology
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AT walsberge whenistheetaleopentopologyafieldtopology
AT yej whenistheetaleopentopologyafieldtopology