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Related papers: L^2-cohomology for von Neumann algebras

200 papers

We study L^2-Betti numbers for von Neumann algebras, as defined by D. Shlyakhtenko and A. Connes, in the presence of a bi-finite correspondence and prove a proportionality formula.

Operator Algebras · Mathematics 2007-05-23 Andreas Thom

In this paper we define $L^{2}$-homology and $L^{2}$-Betti numbers for tracial *-algebras $A$ with respect to a von Neumann subalgebra $B$. When $B$ is reduced to the field of complex numbers we recover the $L^{2}$-Betti numbers of $A$ as…

Operator Algebras · Mathematics 2014-03-26 Miguel Bermudez

We define the notion of L^2 homology and L^2 Betti numbers for a tracial von Neumann algebra, or, more generally, for any involutive algebra with a trace. The definition of these invariants is obtained from the definition of L^2 homology…

Operator Algebras · Mathematics 2007-05-23 Alain Connes , Dimitri Shlyakhtenko

This is a survey of a variety of equivariant (co)homology theories for operator algebras. We briefly discuss a background on equivariant theories, such as equivariant $K$-theory and equivariant cyclic homology. As the main focus, we discuss…

Operator Algebras · Mathematics 2019-02-12 Massoud Amini , Ahmad Shirinkalam

We prove that norm continuous derivations from a von Neumann algebra into the algebra of operators affiliated with its tensor square are automatically continuous for both the strong operator topology and the measure topology. Furthermore,…

Operator Algebras · Mathematics 2018-03-05 Vadim Alekseev , David Kyed

In this article we study cocycles of discrete countable groups with values in l^2(G) and the ring of affiliated operators UG. We clarify properties of the first cohomology of a group G with coefficients in l^2(G) and answer several…

Group Theory · Mathematics 2010-03-22 Jesse Peterson , Andreas Thom

We define for arbitrary modules over a finite von Neumann algebra $\cala$ a dimension taking values in $[0,\infty]$ which extends the classical notion of von Neumann dimension for finitely generated projective $\cala$-modules and inherits…

dg-ga · Mathematics 2008-02-03 Wolfgang Lueck

Let X be a building of uniform thickness q+1. L^2-Betti numbers of X are reinterpreted as von-Neumann dimensions of weighted L^2-cohomology of the underlying Coxeter group. The dimension is measured with the help of the Hecke algebra. The…

Geometric Topology · Mathematics 2009-02-28 Jan Dymara

We compute the l^2-Betti numbers of the complement of a finite collection of affine hyperplanes in complex space. At most one of the l^2-Betti numbers is non-zero.

Algebraic Topology · Mathematics 2007-05-23 M. W. Davis , T. Januszkiewicz , I. J. Leary

We compute the cohomology with trivial coefficients of Lie algebras $\mathfrak{m}_0$ and $\mathfrak{m}_2$ of maximal class over the field $\mathbb{Z}_2$. In the infinite-dimensional case, we show that the cohomology rings…

Rings and Algebras · Mathematics 2016-01-12 Yuri Nikolayevsky , Ioannis Tsartsaflis

We introduce $L^2$-Betti numbers, as well as a general homology and cohomology theory for the standard invariants of subfactors, through the associated quasi-regular symmetric enveloping inclusion of II_1 factors. We actually develop a…

Operator Algebras · Mathematics 2018-04-26 Sorin Popa , Dimitri Shlyakhtenko , Stefaan Vaes

A Rota-Baxter Leibniz algebra is a Leibniz algebra $(\mathfrak{g},[~,~]_{\mathfrak{g}})$ equipped with a Rota-Baxter operator $T : \mathfrak{g} \rightarrow \mathfrak{g}$. We define representation and dual representation of Rota-Baxter…

Rings and Algebras · Mathematics 2023-06-22 Bibhash Mondal , Ripan Saha

In this paper, we consider Leibniz algebras with derivations. A pair consisting of a Leibniz algebra and a distinguished derivation is called a LeibDer pair. We define a cohomology theory for LeibDer pair with coefficients in a…

Rings and Algebras · Mathematics 2020-03-19 Apurba Das

For a von Neumann algebra M on a Hilbert space, A. Connes has constructed a module S and a derivation of M into S, such that M is approximately finite dimensional if and only if that derivation is inner. The paper contains a generalization…

funct-an · Mathematics 2008-02-03 Erik Christensen , Allan M. Sinclair

Rota-Baxter operators have been paid much attention in the last few decades as they have many applications in mathematics and physics. In this paper, our object of study is modified Rota-Baxter operators on Leibniz algebras. We investigate…

Rings and Algebras · Mathematics 2023-11-23 Bibhash Mondal , Ripan Saha

We define cohomology of associative H-pseudoalgebras, and we show that it describes module extensions, abelian pseudoalgebra extensions, and pseudoalgebra first order deformations. We describe in details the same results for the special…

Quantum Algebra · Mathematics 2022-12-19 Jose I. Liberati

In this paper, we define the cohomology of a modified Rota-Baxter Leibniz algebra with coefficients in a suitable representation. As applications of our cohomology, we study formal one-parameter deformations and abelian extensions of…

Rings and Algebras · Mathematics 2022-11-21 Yizheng Li , Dingguo Wang

The aim of this paper is to study the cohomology theory of Reynolds Lie algebras equipped with derivations and to explore related applications. We begin by introducing the concept of Reynolds LieDer pairs. Subsequently, we construct the…

Rings and Algebras · Mathematics 2025-04-24 Basdouri Imed , Sadraoui Mohamed Amin

In this paper we compute the cohomology of certain special cases of nilpotent algebras in a complex \zt-graded vector space of arbitrary finite dimension. These algebras are generalizations of the only two nontrivial complex 2-dimensional…

Rings and Algebras · Mathematics 2010-05-24 Christopher DeCleene , Michael Penkava , Mitch Phillipson

We recast the Foelner condition in an operator algebraic setting and prove that it implies a certain dimension flatness property. Furthermore, it is proven that the Foelner condition generalizes the existing notions of amenability and that…

Operator Algebras · Mathematics 2018-03-05 Vadim Alekseev , David Kyed
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