English
Related papers

Related papers: Compatible actions in semi-abelian categories

200 papers

We introduce and study a Rokhlin-type property for actions of finite groups on (not necessarily unital) C*-algebras. We show that the corresponding crossed product C*-algebras can be locally approximated by C*-algebras that are stably…

Operator Algebras · Mathematics 2014-01-28 Luis Santiago

Abelian groups having partial orderings compatible with their binary operations have long been studied in the literature. In particular, lattice-ordered abelian groups constitute a universal-algebraic variety, and thus form a category which…

Rings and Algebras · Mathematics 2012-01-25 Elijah Stines

We use Janelidze's Categorical Galois Theory to extend Brown and Ellis's higher Hopf formulae for homology of groups to arbitrary semi-abelian monadic categories. Given such a category A and a chosen Birkhoff subcategory B of A, thus we…

Algebraic Topology · Mathematics 2008-08-18 Tomas Everaert , Marino Gran , Tim Van der Linden

In the setting of product systems over group-embeddable monoids, we consider nuclearity of the associated Toeplitz C*-algebra in relation to nuclearity of the coefficient algebra. Our work goes beyond the known cases of single…

Operator Algebras · Mathematics 2025-08-27 Elias G. Katsoulis , Marcelo Laca , Camila F. Sehnem

The rational Borel equivariant cohomology for actions of a compact connected Lie group is determined by restriction of the action to a maximal torus. We show that a similar reduction holds for any compact Lie group $G$ when there is a…

Algebraic Topology · Mathematics 2024-02-14 Sergio Chaves

In this paper we introduce and study a categorical action of the positive part of the Heisenberg Lie algebra on categories of modules over rational Cherednik algebras associated to symmetric groups. We show that the generating functor for…

Representation Theory · Mathematics 2024-08-06 Roman Bezrukavnikov , Ivan Losev

Let $\mathfrak{g}$ be a vector space and $[,],[,]'$ be a pair of Lie brackets on $\mathfrak{g}$. By definition they are compatible if $[,]+[,]'$ is again a Lie bracket. Such pairs play important role in bihamiltonian and $r$-matrix…

Differential Geometry · Mathematics 2012-08-09 Andriy Panasyuk

We introduce an axiomatization of the notion of a semidirect product of locally compact quantum groups and study properties. Our approach is slightly different from the one introduced in the thesis of S.~Roy and, unlike the investigations…

Operator Algebras · Mathematics 2014-10-17 Paweł Kasprzak , Piotr M. Sołtan

We propose the notion of quasi-abelian third cohomology of crossed modules, generalizing Eilenberg and MacLane's abelian cohomology and Ospel's quasi-abelian cohomology, and classify crossed pointed categories in terms of it. We apply the…

Quantum Algebra · Mathematics 2011-11-23 Deepak Naidu

In this paper, we define the notion of crossed modules of groups with action and investigate related structures. Functions for computing of these structures have been written using the GAP computational discrete algebra programming…

Category Theory · Mathematics 2022-01-19 Alper Odabaş , Elis Soylu Yılmaz

We introduce a general definition of a $n$-crossed module of $P$-algebras over an algebraic operad $P$, which coincides with historical definitions in the cases of the operads As and Lie and $n = 1$. We establish a natural isomorphism…

K-Theory and Homology · Mathematics 2025-02-10 Johan Leray , Salim Rivière , Friedrich Wagemann

In this study, using the Brown-Spencer theorem and in the ligth of the works of Norrie, in the category of internal categories within groups, also called group-groupoids, we interpret the notion of actor of a crossed module over groups.…

Category Theory · Mathematics 2018-05-29 Tunçar Şahan

This paper is, essentially, a survey related to the problem of understanding the combinatorics of the action of the monoidal category of finite dimensional modules over a simple finite dimensional Lie algebra on various categories of Lie…

Representation Theory · Mathematics 2025-09-03 Volodymyr Mazorchuk , Xiaoyu Zhu

We prove that an abelian category equipped with an ample sequence of objects is equivalent to the quotient of the category of coherent modules over the corresponding algebra by the subcategory of finite-dimensional modules. In the…

Rings and Algebras · Mathematics 2007-05-23 Alexander Polishchuk

The notion of a coherent unit action on algebraic operads was first introduced by Loday for binary quadratic nonsymmetric operads and generalized by Holtkamp, to ensure that the free objects of the operads carry a Hopf algebra structure.…

Quantum Algebra · Mathematics 2021-08-13 Li Guo , Yunnan Li

A particularly easy, even if for long overlooked way is presented for defining globally arbitrary Lie group actions on smooth functions on Euclidean domains. This way is based on the appropriate use of the usual parametric representation of…

General Mathematics · Mathematics 2007-05-23 Elemer E Rosinger

We introduce the notions of proto-complete, complete, complete* and strong-complete objects in pointed categories. We show under mild conditions on a pointed exact protomodular category that every proto-complete (respectively complete)…

Category Theory · Mathematics 2021-02-22 James Richard Andrew Gray

Partial actions of Hopf algebras can be considered as a generalization of partial actions of groups on algebras. Among important properties of partial Hopf actions, it is possible to assure the existence of enveloping actions. This allows…

Rings and Algebras · Mathematics 2009-10-08 Marcelo Muniz S. Alves , Eliezer Batista

We propose a new definition for the semidirect product of association schemes, generalizing work of Bang, Hirasaka, and Song. We define an action of one scheme on another, and show how one can use such an action to construct all semidirect…

Combinatorics · Mathematics 2011-06-10 Christopher French

A near permutation of a set is a bijection between two cofinite subsets, modulo coincidence on smaller cofinite subsets. Near permutations of a set form its near symmetric group. In this monograph, we define near actions as homomorphisms…

Group Theory · Mathematics 2019-01-17 Yves Cornulier