English

Hopf-Galois structures on cyclic extensions and skew braces with cyclic multiplicative group

Group Theory 2022-10-28 v3 Number Theory Rings and Algebras

Abstract

Let GG and NN be two finite groups of the same order. It is well-known that the existences of the following are equivalent: (a) a Hopf-Galois structure of type NN on any Galois GG-extension; (b) a skew brace with additive group NN and multiplicative group GG; (c) a regular subgroup isomorphic to GG in the holomorph of NN. We shall say that (G,N)(G,N) is realizable when any of the above exists. Fixing NN to be a cyclic group, W. Rump (2019) has determined the groups GG for which (G,N)(G,N) is realizable. In this paper, fixing GG to be a cyclic group instead, we shall give a complete characterization of the groups NN for which (G,N)(G,N) is realizable.

Keywords

Cite

@article{arxiv.2112.08894,
  title  = {Hopf-Galois structures on cyclic extensions and skew braces with cyclic multiplicative group},
  author = {Cindy Tsang},
  journal= {arXiv preprint arXiv:2112.08894},
  year   = {2022}
}

Comments

Fixed some typos