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Related papers: Gyrogroup extensions and semi cross product

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We consider limits over categories of extensions and show how certain well-known functors on the category of groups turn out as such limits. We also discuss higher (or derived) limits over categories of extensions.

Category Theory · Mathematics 2009-05-21 Roman Mikhailov , Inder Bir S. Passi

In the context of finite tensor products of Hilbert spaces, we prove that similarity of a tensor product of operator semigroups to a contraction semigroup is equivalent to the corresponding similarity for each factor, after an appropriate…

Functional Analysis · Mathematics 2025-09-04 J. Oliva-Maza , Y. Tomilov

The aim of this paper is to study co-prolongations of central extensions. We construct the obstruction theory for co-prolongations and classify the equivalence classes of these by kernels of a homomorphisms between 2-dimensional cohomology…

Group Theory · Mathematics 2013-09-13 Nguyen Tien Quang , Doan Trong Tuyen , Nguyen Thi Thu Thuy

In this article, we discuss the Grothendieck group completion (GGC) of a gyrogroup. Consequently, we show that there is a one to one correspondence between actions and representations of a gyrogroup, and actions and representations of its…

Group Theory · Mathematics 2021-06-23 Akshay Kumar , Mani Shankar Pandey , Seema Kushwaha , Sumit Kumar Upadhyay

This paper aims to introduce a more general definition of quasirandom groups and generalize several well-known results in the literature in this new setting. More precisely, let $G$ be a semi-direct product of groups and $X\subseteq G$, we…

Combinatorics · Mathematics 2023-08-28 Thang Pham , Boqing Xue

Skew morphisms, which generalise automorphisms for groups, provide a fundamental tool for the study of regular Cayley maps and, more generally, for finite groups with a complementary factorisation $X = GY$, where $Y$ is cyclic and core-free…

Group Theory · Mathematics 2023-09-08 Wenjuan Luo , Hao Yu

The goal of the paper "A new graph over semi-direct products of groups" is to define a graph \Gamma(G) on a group G when G splits over a normal subgroup. We demonstrate herein that the graph is ill-defined. We also attempt to ascertain…

Group Theory · Mathematics 2017-01-31 John K. McVey

Let $\mathscr X$ be an $\infty$-topos, for example the $\infty$-category of simplicial sheaves on a Grothendieck site. Then $\infty$-group sheaves are group objects in $\mathscr X$. Let $A\in\mathrm{Grp}\mathscr X$ be such a group object.…

Algebraic Geometry · Mathematics 2016-12-30 Pal Zsamboki

This thesis is dedicated to developing a dilation theory for semigroups of completely positive maps. The first part treats two-parameter semigroups, and contains also contributions to dilation theory of product system representations. The…

Operator Algebras · Mathematics 2010-03-02 Orr Shalit

A generalization to the categorical notion of biproduct, called semibiproduct, which in the case of groups covers classical semidirect products, has recently been analysed in the category of monoids with surprising results in the…

Category Theory · Mathematics 2022-08-29 Nelson Martins-Ferreira

For a finite group $G$, a $G$-crossed braided fusion category is $G$-graded fusion category with additional structures, namely a $G$-action and a $G$-braiding. We develop the notion of $G$-crossed braided zesting: an explicit method for…

Quantum Algebra · Mathematics 2024-02-21 Colleen Delaney , César Galindo , Julia Plavnik , Eric Rowell , Qing Zhang

In this work we present a new definition to the Partial Crossed Product by actions of inverse semigroups in a C^*-algebra, without using the covariant representations as Sieben did in [5]. Also we present an isomorphism between the partial…

Operator Algebras · Mathematics 2008-05-26 Ruy Exel , Felipe Vieira

We prove a structure result on proper extensions of two-sided restriction semigroups in terms of partial actions, generalizing respective results for monoids and for inverse semigroups and upgrading the latter. We introduce and study…

Rings and Algebras · Mathematics 2024-10-29 Mikhailo Dokuchaev , Mykola Khrypchenko , Ganna Kudryavtseva

In this article, we introduce rotation groups as a common generalisation of Coxeter groups and graph products of groups (including right-angled Artin groups). We characterise algebraically these groups by presentations (periagroups) and we…

Group Theory · Mathematics 2026-02-17 Anthony Genevois

We develop a theory of split extensions of unitary magmas, which includes defining such extensions and describing them via suitably defined semidirect product, yielding an equivalence between the categories of split extensions and of…

Category Theory · Mathematics 2020-03-20 Marino Gran , George Janelidze , Manuela Sobral

In this paper, we study gyro-groups associated to groups, group extensions admitting gyro-sections, and corresponding co-homologies. We also describe the obstructions in terms of co-homomology. The notion of gyro-Schur Multiplier and that…

Group Theory · Mathematics 2023-02-21 Ramji Lal , Vipul Kakkar

In this paper there are considered some scalar valued groupoid bihomomorphism structures, being in fact the groupoid counterparts of the inner product notion originally defined for vectors. These bihomomorphisms, called here the semi-inner…

Group Theory · Mathematics 2013-01-07 Piotr Multarzyński

In this paper a method of constructing a semiorthogonal decomposition of the derived category of $G$-equivariant sheaves on a variety $X$ is described, provided that the derived category of sheaves on $X$ admits a semiorthogonal…

Algebraic Geometry · Mathematics 2015-10-22 Alexey Elagin

We study and relate certain actions and extensions involving 2-groups.

Algebraic Topology · Mathematics 2009-09-25 Alejandro Adem , Ergün Yalçin

In this paper using split extensions of group-groupoids we obtain the notion of crossed modules over group-grouoids which are also called 2-groups and we prove a categorical equivalence of these types of crossed modules and double…

Category Theory · Mathematics 2021-02-16 Sedat Temel , Tunçar Şahan , Osman Mucuk