English

Hopf-Galois structures on separable field extensions of degree related to Cunningham chains

Group Theory 2025-08-06 v1

Abstract

The past few years have seen Hopf--Galois structures on extensions of squarefree degree studied in various contexts. The Galois case was fully explored by Alabdali and Byott in 2020, followed by a first attempt at generalising these results to include non-normal extensions by Byott and Martin-Lyons; their work looks at separable extensions of degree pqpq with p,qp,q distinct odd primes, and p=2q+1p=2q+1. This paper extends the latter work further by considering separable extensions of squarefree degree n=p1...pmn=p_1...p_m where each pair of consecutive primes pi,pi+1p_i,p_{i+1} are related by pi=2pi+1+1p_i=2p_{i+1}+1.

Keywords

Cite

@article{arxiv.2508.03384,
  title  = {Hopf-Galois structures on separable field extensions of degree related to Cunningham chains},
  author = {Andrew Darlington},
  journal= {arXiv preprint arXiv:2508.03384},
  year   = {2025}
}

Comments

27 pages. Comments and suggestions are very much welcome!