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Related papers: Skew braces of size $pq$

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The aim of this paper is to study supersoluble skew braces, a class of skew braces that encompasses all finite skew braces of square-free order. It turns out that finite supersoluble skew braces have Sylow towers, and that in an arbitrary…

Rump proved in \cite[Theorem~1]{Rump2018ClassificationOC} that if a finite skew brace has cyclic additive group, then its multiplicative group is solvable and almost Sylow cyclic. In this paper we show that this rigidity persists when the…

Group Theory · Mathematics 2026-03-25 Marco Damele

Let $G$ be a finite nonabelian group, and let $\psi:G\to G$ be a homomorphism with abelian image. We show how $\psi$ gives rise to two Hopf-Galois structures on a Galois extension $L/K$ with Galois group (isomorphic to) $G$; one of these…

Group Theory · Mathematics 2020-12-15 Alan Koch

In this paper the category of opposite brace triples is introduced in a general braided monoidal setting. Under cocommutativity, it is proved to be isomorphic to the category of Hopf braces. Furthermore, if one considers the subcategories…

Rings and Algebras · Mathematics 2026-05-11 Ramón González Rodríguez , Brais Ramos Pérez

In this paper, we continue the enumeration of Schur rings over cyclic groups. Cyclic groups of semiprime order $pq$, where $p$ and $q$ are distinct primes, are considered. Additionally, cyclic groups of order $4p$ are considered.

Group Theory · Mathematics 2021-03-18 Joseph Keller , Andrew Misseldine , Max Sullivan

We examine the pointed protomodular category SKB of left skew braces. We study the notion of commutator of ideals in a left skew brace. Notice that in the literature, "product" of ideals of skew braces is often considered. We show that…

Category Theory · Mathematics 2022-05-10 Dominique Bourn , Alberto Facchini , Mara Pompili

Let $G$ be a nonabelian group. We show how a collection of compatible endomorphisms $\psi_i:G\to G$ such that $\psi_i([G,G])\le Z(G)$ for all $i$ allows us to construct a family of bi-skew braces called a brace block. We relate this…

Group Theory · Mathematics 2022-06-16 Alan Koch

Let $k$ be an algebraically closed field of characteristic $0$. In this paper, we obtain the structure theorems for semisimple Hopf algebras of dimension $p^2q^2$ over $k$, where $p,q$ are prime numbers with $p^2<q$. As an application, we…

Rings and Algebras · Mathematics 2011-01-11 Jingcheng Dong

Skew braces have recently attracted attention as a method to study set-theoretical solutions of the Yang-Baxter equation. Here, we present a new approach to these solutions by studying Hopf algebras in the category, $\mathrm{SupLat}$, of…

Quantum Algebra · Mathematics 2020-09-29 Aryan Ghobadi

We consider Hopf-Galois structures on separable (but not necessarily normal) field extensions $L/K$ of squarefree degree $n$. If $E/K$ is the normal closure of $L/K$ then $G=\mathrm{Gal}(E/K)$ can be viewed as a permutation group of degree…

Number Theory · Mathematics 2021-06-15 Nigel P. Byott , Isabel Martin-Lyons

A fibration of ${\mathbb R}^n$ by oriented copies of ${\mathbb R}^p$ is called skew if no two fibers intersect nor contain parallel directions. Conditions on $p$ and $n$ for the existence of such a fibration were given by Ovsienko and…

Algebraic Topology · Mathematics 2015-09-28 Michael Harrison

We present a different version of the well-known connection between Hopf--Galois structures and skew braces, building on a recent paper of A. Koch and P. J. Truman. We show that the known results that involve this connection easily carry…

Number Theory · Mathematics 2023-02-28 L. Stefanello , S. Trappeniers

We discuss the (first) Sylow theorem for certain classes of finite skew braces, proving it to hold true when the skew brace is two-sided, bi-skew, right nilpotent, $\lambda$-homomorphic or supersoluble. We also show it to hold true for…

Rings and Algebras · Mathematics 2026-04-22 A. Caranti , I. Del Corso , M. Di Matteo , M. Ferrara , M. Trombetti

Our primary focus is on the theory of skew braces, specifically exploring their connection with combinatorial solutions to the Yang-Baxter equation. Skew braces have recently emerged as intriguing algebraic structures, and their link to the…

Rings and Algebras · Mathematics 2024-12-05 Leandro Vendramin

We develop the theory of Schur covers of finite skew braces. We prove the existence of at least one Schur cover. We also compute several examples. We prove that different Schur covers are isoclinic. Finally, we prove that Schur covers have…

Group Theory · Mathematics 2024-02-01 T. Letourmy , L. Vendramin

The present article is devoted to introduce the notion of Hopf bracoid in the braided monoidal framework as the quantum version of skew bracoids, which have been presented by Martin-Lyons and Paul J. Truman. Taking into account that Hopf…

Rings and Algebras · Mathematics 2025-04-08 José Manuel Fernández Vilaboa , Ramón González Rodríguez , Brais Ramos Pérez

The notion of a pre-truss, that is, a set that is both a heap and a semigroup is introduced. Pre-trusses themselves as well as pre-trusses in which one-sided or two-sided distributive laws hold are studied. These are termed near-trusses and…

Rings and Algebras · Mathematics 2020-07-24 Tomasz Brzeziński , Stefano Mereta , Bernard Rybołowicz

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 $ L/K $ whose Galois group is the semidirect product of a normal subgroup $ A $ and a subgroup $ B $,…

Group Theory · Mathematics 2025-06-06 Paul J. Truman

L. Childs has defined a skew brace $(G, \cdot, \circ)$ to be a bi-skew brace if $(G, \circ, \cdot)$ is also a skew brace, and has given applications of this concept to the equivalent theory of Hopf-Galois structures. The goal of this paper…

Group Theory · Mathematics 2020-07-28 A. Caranti

Hopf braces are the quantum analogues of skew braces and, as such, their cocommutative counterparts provide solutions to the quantum Yang-Baxter equation. We investigate various properties of categories related to Hopf braces. In…

Quantum Algebra · Mathematics 2025-10-03 Ana Agore , Alexandru Chirvasitu