Classification of the types for which every Hopf--Galois correspondence is bijective
Abstract
Let be any finite Galois extension with Galois group . It is known by Chase and Sweedler that the Hopf--Galois correspondence is injective for every Hopf--Galois structure on , but it need not be bijective in general. Hopf--Galois structures are known to be related to skew braces, and recently, the first-named author and Trappeniers proposed a new version of this connection with the property that the intermediate fields of in the image of the Hopf--Galois correspondence are in bijection with the left ideals of the associated skew brace. As an application, they classified the groups for which the Hopf--Galois correspondence is bijective for every Hopf--Galois structure on any -Galois extension. In this paper, using a similar approach, we shall classify the groups for which the Hopf--Galois correspondence is bijective for every Hopf--Galois structure of type on any Galois extension.
Keywords
Cite
@article{arxiv.2406.15800,
title = {Classification of the types for which every Hopf--Galois correspondence is bijective},
author = {Lorenzo Stefanello and Cindy Tsang},
journal= {arXiv preprint arXiv:2406.15800},
year = {2024}
}
Comments
10 pages; modified the definitions of H in Examples 3.1 to 3.5 based on referee's suggestions