The Neukirch–Uchida theorem with restricted ramification

Let be a number field and a set of primes of . We write for the maximal extension of unramified outside and for its Galois group. In this paper, we prove the following generalization of the Neukirch–Uchida theorem under some assumptions: “For , let be a number field and a set of primes of . If and a...

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Bibliographic Details
Published inJournal für die reine und angewandte Mathematik Vol. 2022; no. 785; pp. 187 - 217
Main Author Shimizu, Ryoji
Format Journal Article
LanguageEnglish
Published De Gruyter 01.04.2022
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Summary:Let be a number field and a set of primes of . We write for the maximal extension of unramified outside and for its Galois group. In this paper, we prove the following generalization of the Neukirch–Uchida theorem under some assumptions: “For , let be a number field and a set of primes of . If and are isomorphic, then and are isomorphic.” Here the main assumption is that the Dirichlet density of is not zero for at least one . A key step of the proof is to recover group-theoretically the -adic cyclotomic character of an open subgroup of for some prime number
ISSN:0075-4102
1435-5345
DOI:10.1515/crelle-2021-0090