Some interactions between Hopf Galois extensions and noncommutative rings

TL;DR

This paper surveys the interactions between Hopf Galois extensions and noncommutative rings, providing examples, calculations, and recent advances to deepen understanding of both theories and their connections.

Contribution

It systematically develops questions, properties, and examples linking Hopf Galois extensions with noncommutative rings, highlighting recent progress and approaches from quantum torsors and Galois systems.

Findings

Advances in characterizing ring-theoretic properties of noncommutative rings.

Development of examples illustrating Hopf Galois systems.

Systematic survey connecting Hopf Galois extensions with noncommutative ring theory.

Abstract

In this paper, our objects of interest are Hopf Galois extensions (e.g., Hopf algebras, Galois field extensions, strongly graded algebras, crossed products, principal bundles, etc.) and families of noncommutative rings (e.g., skew polynomial rings, PBW extensions and skew PBW extensions, etc.). We collect and systematize questions, problems, properties and recent advances in both theories by explicitly developing examples and doing calculations that are usually omitted in the literature. In particular, for Hopf Galois extensions we consider approaches from the point of view of quantum torsors (also known as quantum heaps) and Hopf Galois systems, while for some families of noncommutative rings we present advances in the characterization of ring-theoretic and homological properties. Every developed topic is exemplified with abundant references to classic and current works, so this paper serves as a survey for those interested in either of the two theories. Throughout, interactions between both are presented.