English
Related papers

Related papers: Embedding group algebras into finite von Neumann r…

200 papers

Let $G$ be a finite group and let $k$ be a sufficiently large finite field. Let $R(G)$ denote the character ring of $G$ (i.e. the Grothendieck ring of the category of ${\mathbb{C}}G$-modules). We study the structure and the representations…

Representation Theory · Mathematics 2008-07-07 Cédric Bonnafé

The Isomorphism Conjecture is a conceptional approach towards a calculation of the algebraic K-theory of a group ring RG, where G is an infinite group. In this paper we prove the conjecture in dimensions n<2 for fundamental groups of closed…

Algebraic Topology · Mathematics 2007-05-23 Arthur Bartels , Tom Farrell , Lowell Jones , Holger Reich

We prove that every finitely presented self-similar group embeds in a finitely presented simple group. This establishes that every group embedding in a finitely presented self-similar group satisfies the Boone-Higman conjecture. The simple…

Group Theory · Mathematics 2025-01-22 Matthew C. B. Zaremsky

Let $\Gamma$ be a finitely generated torsion-free group. We show that the statement of $\Gamma$ being virtually abelian is equivalent to the statement that the $*$-regular closure of the group ring $\mathbb{C}[\Gamma]$ in the algebra of…

Group Theory · Mathematics 2023-03-07 Joan Claramunt , Lukasz Grabowski

The algebras of Kleinian type are finite dimensional semisimple rational algebras $A$ such that the group of units of an order in $A$ is commensurable with a direct product of Kleinian groups. We classify the Schur algebras of Kleinian type…

Representation Theory · Mathematics 2007-05-23 Gabriela Olteanu , Angel del Rio

In arXiv:1109.6438v1 [math.AG] we introduced and studied a notion of algebraic entropy. In this paper we will give an application of algebraic entropy in proving Kunz Regularity Criterion for all contracting self-maps of finite length of…

Commutative Algebra · Mathematics 2011-10-18 Mahdi Majidi-Zolbanin , Nikita Miasnikov , Lucien Szpiro

If $R$ is a regular and semiartinian ring, it is proved that the following conditions are equivalent: (1) $R$ is unit-regular, (2) every factor ring of $R$ is directly finite, (3) the abelian group $K_0(R)$ is free and admits a basis which…

Rings and Algebras · Mathematics 2016-07-14 Giuseppe Baccella , Leonardo Spinosa

We prove the Farrell-Jones Isomorphism Conjecture about the algebraic K-theory of a group ring RG in the case where the group G is the fundamental group of a closed Riemannian manifold with strictly negative sectional curvature. The…

Algebraic Topology · Mathematics 2007-05-23 A. Bartels , H. Reich

It this note we investigate the structure of the group of \sigma-unitary units in some noncommutative modular group algebras KG, where \sigma is a non-classical ring involution of KG.

Rings and Algebras · Mathematics 2008-03-04 Victor Bovdi , Tibor Rozgonyi

The Realization Problem for (von Neumann) regular rings asks what are the conical refinement monoids which can be obtained as the monoids of isomorphism classes of finitely generated projective modules over a regular ring. The analogous…

Rings and Algebras · Mathematics 2015-12-29 P. Ara , K. R. Goodearl

In this paper we study actions of locally compact quantum groups on von Neumann algebras and prove that every action has a canonical unitary implementation, paralleling Haagerup's classical result on the unitary implementation of a locally…

Operator Algebras · Mathematics 2007-05-23 Stefaan Vaes

The article gives the second part of the treatise on Regular Algebraic $K$-theory (Sections V & VI) of the author. Regular algebraic $K$-theory for groups is a homology theory for discrete groups closely connected to (but different from)…

K-Theory and Homology · Mathematics 2024-10-11 Ulrich Haag

In his study of amenable unitary representations, M. E. B. Bekka asked if there is an analogue for such representations of the remarkable fixed-point property for amenable groups. In this paper, we prove such a fixed-point theorem in the…

Operator Algebras · Mathematics 2007-05-23 Anthony T. Lau , Alan L. T. Paterson

Let V(KG) be a normalised unit group of the modular group algebra of a finite p-group G over the field K of p elements. We introduce a notion of symmetric subgroups in V(KG) as subgroups invariant under the action of the classical…

Rings and Algebras · Mathematics 2008-01-08 A. B. Konovalov , A. G. Krivokhata

Let $R$ be a commutative ring and $\Gamma$ be an infinite discrete group. The algebraic $K$-theory of the group ring $R[\Gamma]$ is an important object of computation in geometric topology and number theory. When the group ring is…

K-Theory and Homology · Mathematics 2016-07-04 Gunnar Carlsson , Boris Goldfarb

Let $RG$ be the gruop ring of the group $G$ over ring $R$ and $\mathscr{U}(RG)$ be its unit group. Finding the structure of the unit group of a finite group ring is an old topic in ring theory. In, G. Tang et al: Unit Groups of Group…

Rings and Algebras · Mathematics 2020-04-08 Ali Ashja'

For a class of wreath-like product groups with property (T), we describe explicitly all the embeddings between their von Neumann algebras. This allows us to provide a continuum of ICC groups with property (T) whose von Neumann algebras are…

Operator Algebras · Mathematics 2025-11-12 Ionut Chifan , Adrian Ioana , Denis Osin , Bin Sun

Let $KG$ be the group ring of a group $G$ over a commutative ring $K$ with unity. The rings $KG$ are described for which $xx^\sigma=x^\sigma x$ for all $x=\sum_{g\in G}\alpha_gg\in KG$, where \quad $x\mapsto x^\sigma=~\sum_{g\in…

Rings and Algebras · Mathematics 2008-04-08 V. A. Bovdi , S. Siciliano

We classify finite groups $G$, such that the group algebra, $\mathbb{Q}G$ (over the field of rational numbers $\mathbb{Q}$), is the direct product of the group algebra $\mathbb{Q}[G/N]$ of a proper factor group $G/N$, and some division…

Group Theory · Mathematics 2019-05-22 Frieder Ladisch

We investigate the relative assembly map from the family of finite subgroups to the family of virtually cyclic subgroups for the algebraic $K$-theory of twisted group rings of a group G with coefficients in a regular ring R or, more…

K-Theory and Homology · Mathematics 2024-08-02 Wolfgang Lueck