English

On Galois extensions with prescribed decomposition groups

Number Theory 2021-07-22 v3

Abstract

We study the inverse Galois problem with local conditions. In particular, we ask whether every finite group occurs as the Galois group of a Galois extension of Q\mathbb{Q} all of whose decomposition groups are cyclic (resp., abelian). This property is known for all solvable groups due to Shafarevich's solution of the inverse Galois problem for those groups. It is however completely open for nonsolvable groups. In this paper, we provide general criteria to attack such questions via specialization of function field extensions, and in particular give the first infinite families of Galois realizations with only cyclic decomposition groups and with nonsolvable Galois group. We also investigate the analogous problem over global function fields.

Keywords

Cite

@article{arxiv.1911.08742,
  title  = {On Galois extensions with prescribed decomposition groups},
  author = {Kwang-Seob Kim and Joachim König},
  journal= {arXiv preprint arXiv:1911.08742},
  year   = {2021}
}

Comments

Updated to the published version. Additionally, inserted corrigendum addressing a minor error on p.17

R2 v1 2026-06-23T12:21:54.726Z