activity
20102026
most citedTowards a Generalisation of Noether's Theorem to Nonclassical Hopf-Galois Structures

5 citations · 17 across the 14 of their papers we have counts for

collaborators

20 papers

math.GR2026

Bidihedral skew braces

Alan Koch, Paul J. Truman

We classify skew braces with additive and multiplicative groups both isomorphic to the dihedral group . As a consequence, we obtain an alternative proof of the classificat…

math.GR2026★ 1 cited

Analogues of Sylow's first theorem, Cauchy's theorem, and Hall's theorem for skew braces

Paul J. Truman

We establish an unconditional analogue of Sylow's first theorem for finite skew braces, and deduce an analogue of Cauchy's theorem. We also prove an analogue of the existence part…

math.GR2026

Bicyclic biskew braces

Hal Simpson, Paul J. Truman

We study finite braces whose additive and multiplicative groups are both cyclic. We reinterpret the classification of these braces from the perspective of regular subgroups of perm…

math.GR2025

On some semidirect products of skew braces arising in Hopf-Galois theory

Paul J. Truman

We classify skew braces that are the semidirect product of an ideal and a left ideal. As a consequence, given a Galois extension of fields whose Galois group is the semidir…

math.GR2025

Constructing skew bracoids via abelian maps, and solutions to the {Y}ang-{B}axter equation

Alan Koch, Paul J. Truman

We show how one can use the skew braces constructed using abelian maps to generate families of skew bracoids as defined by Martin-Lyons and Truman. Under certain circumstances, the…

math.RA2024★ 1 cited

Skew bracoids containing a skew brace

Ilaria Colazzo, Alan Koch, Isabel Martin-Lyons +1

Skew bracoids have been shown to have applications in Hopf-Galois theory. We show that a certain family of skew bracoids correspond bijectively with left cancellative semibraces. A…

math.GR2023

Skew bracoids

Isabel Martin-Lyons, Paul J. Truman

Skew braces are intensively studied owing to their wide ranging connections and applications. We generalize the definition of a skew brace to give a new algebraic object, which we…

math.NT2022

On -conjugate Hopf-Galois structures

Paul J. Truman

The Hopf-Galois structures admitted by a Galois extension of fields with Galois group correspond bijectively with certain subgroups of . We use a…

math.GR2020★ 1 cited

Abelian fixed point free endomorphisms and the Yang-Baxter equation

Alan Koch, Laura Stordy, Paul J. Truman

We obtain a simple family of solutions to the set-theoretic Yang-Baxter equation, one which depends only on considering special endomorphisms of a finite group. We show how such an…

math.GR2020

Skew left braces and isomorphism problems for Hopf-Galois structures on Galois extensions

Alan Koch, Paul J. Truman

Given a finite group , we study certain regular subgroups of the group of permutations of , which occur in the classification theories of two types of algebraic objects:…

math.GR2019

Opposite skew left braces and applications

Alan Koch, Paul J. Truman

Given a skew left brace , we introduce the notion of an "opposite" skew left brace , which is closely related to the concept of the opposite of a group…

math.NT2019

Hopf-Galois module structure of tamely ramified radical extensions of prime degree

Paul J Truman

Let be a number field and let be a tamely ramified radical extension of prime degree . If contains a primitive root of unity then is a c…

math.RA2018★ 5 cited

The structure of Hopf algebras giving Hopf-Galois structures on Quaternionic extensions

Stuart Taylor, Paul J Truman

Let be a Galois extension of fields with Galois group isomorphic to the quaternion group of order . We describe all of the Hopf-Galois structures admitted by , an…

math.NT2017

Isomorphism problems for Hopf-Galois structures on separable field extensions

Alan Koch, Timothy Kohl, Paul J. Truman +1

Let be a finite separable extension of fields whose Galois closure has group . Greither and Pareigis have used Galois descent to show that a Hopf algebra givin…

math.NT2017

Normality and Short Exact Sequences of Hopf-Galois Structures

Alan Koch, Timothy Kohl, Paul J. Truman +1

Every Hopf-Galois structure on a finite Galois extension where corresponds uniquely to a regular subgroup , normalized by $λ(G)\l…

math.NT2017★ 4 cited

The Structure of Hopf Algebras Acting on Dihedral Extensions

Alan Koch, Timothy Kohl, Paul J. Truman +1

We discuss isomorphism questions concerning the Hopf algebras that yield Hopf-Galois structures for a fixed separable field extension . We study in detail the case where …

math.NT2017

Commutative Hopf-Galois module structure of tame extensions

Paul J. Truman

We prove three theorems concerning the Hopf-Galois module structure of fractional ideals in a finite tamely ramified extension of -adic fields or number fields which is -…

math.NT2016

Commuting Hopf-Galois Structures on a Separable Extension

Paul J. Truman

Let be a finite separable extension of local or global fields in any characteristic, let be two Hopf algebras giving Hopf-Galois structures on the extensio…

math.NT2014

Canonical Nonclassical Hopf-Galois Module Structure of Nonabelian Galois Extensions

Paul J Truman

Let be a finite Galois extension of local or global fields in characteristic or with nonabelian Galois group , and let be a -stable fractional i…

math.NT2010★ 5 cited

Towards a Generalisation of Noether's Theorem to Nonclassical Hopf-Galois Structures

Paul J. Truman

We study the nonclassical Hopf-Galois module structure of rings of algebraic integers in some extensions of -adic fields and number fields which are at most tamely ramified. W…