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In this article we describe the $G_{comp}\times G_{comp}$-equivariant topological $K$-ring of a {\em cellular} toroidal embedding $\mathbb{X}$ of a complex connected reductive algebraic group $G$. In particular, our results extend the…

Algebraic Geometry · Mathematics 2025-06-11 Alexis Tchoudjem , V. Uma

We introduce a new notion of twisted actions of inverse semigroups and show that they correspond bijectively to certain regular Fell bundles over inverse semigroups, yielding in this way a structure classification of such bundles. These…

Operator Algebras · Mathematics 2014-02-26 Alcides Buss , Ruy Exel

Given a group G acting on a ring R, one can construct the skew group ring R*G. Skew group rings have been studied in depth, but necessary and sufficient conditions for the simplicity of a general skew group ring are not known. In this…

Rings and Algebras · Mathematics 2007-05-23 Kathi Crow

Let $K$ be a finite group and let $G$ be a finite group acting on $K$ by automorphisms. In this paper we study two different but intimately related subjects: on the one side we classify all possible multiplicative and associative structures…

Quantum Algebra · Mathematics 2021-03-08 César Galindo , Ismael Gutiérrez , Bernardo Uribe

In this paper, we study the classes of rings in which every proper (regular) ideal can be factored as an invertible ideal times a nonempty product of proper radical ideals. More precisely, we investigate the stability of these properties…

Commutative Algebra · Mathematics 2020-09-15 Malik Tusif Ahmed , Najib Mahdou , Youssef Zahir

Let $K$ be an algebraically closed field of characteristic zero. Algebraic structures of a specific type (e.g. algebras or coalgebras) on a given vector space $W$ over $K$ can be encoded as points in an affine space $U(W)$. This space is…

Representation Theory · Mathematics 2020-07-09 Ehud Meir

We prove that the twisted group C*-algebra of an acylindrically hyperbolic group -- not necessarily having trivial finite radical -- has stable rank one.

Operator Algebras · Mathematics 2024-03-12 Sven Raum

The paper gives a short account of the contents of "Regular Algebraic K-Theory For Groups" by the author and its connections with other homology and K-theories.

K-Theory and Homology · Mathematics 2014-02-05 Ulrich Haag

Twisted $K$-homology corresponds to $D$-branes in string theory. In this paper we compare two different models of geometric twisted $K$-homology and get their equivalence. Moreover, we give another description of geometric twisted…

K-Theory and Homology · Mathematics 2014-11-17 Bei Liu

We study the structure of abelian extensions of the group $L_qG$ of $q$-differentiable loops (in the Sobolev sense), generalizing from the case of central extension of the smooth loop group. This is motivated by the aim of understanding the…

Differential Geometry · Mathematics 2012-03-09 Pedram Hekmati , Jouko Mickelsson

In this paper, we are mainly interested in the two questions "which are the commutative rings on which every finitely presented modules is [Formula: see text]-periodic (respectively, [Formula: see text]-periodic)?". It is proved that these…

Commutative Algebra · Mathematics 2022-03-08 Driss Bennis , François Couchot

We characterize the seminormality of an affine semigroup ring in terms of the dualizing complex, and the normality of a Cohen-Macaulay semigroup ring by the "shape" of the canonical module. We also characterize the seminormality of a toric…

Commutative Algebra · Mathematics 2014-12-09 Kohji Yanagawa

Let $RG$ denote the group ring of the torsion group $G$ over a commutative ring $R$ with identity. In this paper we present proofs of some statements that appear without to be proved in the literature. We establish the valid implications…

Rings and Algebras · Mathematics 2022-12-02 Brayan S. Flórez-Burbano , Alexander Holguín-Villa , John H. Castillo

We provide the Krull-Remak-Schmidt decomposition of group algebras of the form $k[G]$ where $k$ is a field, which includes fields with prime characteristic, and $G$ a finite abelian group. We achieved this by studying the geometric…

Commutative Algebra · Mathematics 2024-08-28 Robert Christian Subroto

We give a survey of some recent results on the fusion semirings of compact quantum groups (computations of and applications to discrete quantum groups) by using the following simplifying terminology: we say that a compact quantum group G is…

Quantum Algebra · Mathematics 2007-05-23 Teodor Banica

Let U be the group of units of an infinite twisted group algebra K_\lambda G over a field K. We describe the maximal FC-subgroup of U and give a characterization of U with finitely conjugacy classes. In the case of group algebras we obtain…

Rings and Algebras · Mathematics 2008-03-19 Victor Bovdi

After recalling some basic facts about F-wound commutative unipotent algebraic groups over an imperfect field F we study their regular integral models over Dedekind schemes of positive characteristic and compute the group of isomorphisms…

Algebraic Geometry · Mathematics 2021-05-17 Igor Dolgachev

We give a characterization of groups with twisted p-periodic cohomology in terms of group actions on mod p homology spheres. An equivalent algebraic characterization of such groups is also presented.

Group Theory · Mathematics 2014-06-03 Guido Mislin , Olympia Talelli

Let $k$ be a regular ring, and let $A,B$ be essentially finite type $k$-algebras. For any functor $F:{D}(A)\times\dots\times{D}(A)\to{D}(B)$ between their derived categories, we define its twist…

Algebraic Geometry · Mathematics 2016-07-07 Liran Shaul

Let $G$ be a compact connected Lie group and $K$ a closed connected subgroup. Assume that the order of any torsion element in the integral cohomology of $G$ and $K$ is invertible in a given principal ideal domain $k$. It is known that in…

Algebraic Topology · Mathematics 2021-11-24 Matthias Franz