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We provide a general criterion to deduce maximal amenability of von Neumann subalgebras $L\Lambda \subset L\Gamma$ arising from amenable subgroups $\Lambda$ of discrete countable groups $\Gamma$. The criterion is expressed in terms of…

Operator Algebras · Mathematics 2015-04-20 Rémi Boutonnet , Alessandro Carderi

In this thesis, we introduce a new cohomology theory associated to a Lie 2-algebras and a new cohomology theory associated to a Lie 2-group. These cohomology theories are shown to extend the classical cohomology theories of Lie algebras and…

Differential Geometry · Mathematics 2018-11-09 Camilo Angulo

The notion of an action of a locally compact quantum group on a von Neumann algebra is studied from the amenability point of view. Various Reiter's conditions for such an action are discussed. Several applications to some specific actions…

Operator Algebras · Mathematics 2009-06-30 M. Ramezanpour , H. R. Ebrahimi Vishki

Let $\mathbb{G}$ be a compact quantum group and $A\subseteq B$ an inclusion of $\sigma$-finite $\mathbb{G}$-dynamical von Neumann algebras. We prove that the $\mathbb{G}$-inclusion $A\subseteq B$ is strongly equivariantly amenable if and…

Operator Algebras · Mathematics 2025-04-10 K. De Commer , J. De Ro

We show that the amenability of a locally compact group $G$ is equivalent to a factorization property of $VN(G)$ which is given by $ VN(G) = <VN(G)^*VN(G)>$. This answer partially two problems proposed by Z. Hu and M. Neufang in their…

Operator Algebras · Mathematics 2011-08-16 Denis Poulin

We define and study notions of amenability and skew-amenability of continuous actions of topological groups on compact topological spaces. Our main motivation is the question under what conditions amenability of a topological group passes…

Group Theory · Mathematics 2025-10-27 Vadim Alekseev , Hiroshi Ando , Friedrich Martin Schneider , Andreas Thom

The original definition of amenability given by von Neumann in the highly non-constructive terms of means was later recast by Day using approximately invariant probability measures. Moreover, as it was conjectured by Furstenberg and proved…

Functional Analysis · Mathematics 2020-05-29 Theo Bühler , Vadim A. Kaimanovich

Building on our previous work, we study the non-relative homology of quantum group convolution algebras. Our main result establishes the equivalence of amenability of a locally compact quantum group $\mathbb{G}$ and 1-injectivity of…

Operator Algebras · Mathematics 2016-03-16 Jason Crann

A theory of Galois co-objects for von Neumann bialgebras is introduced. This concept is closely related to the notion of comonoidal W*-Morita equivalence between von Neumann bialgebras, which is a Morita equivalence taking the…

Operator Algebras · Mathematics 2013-08-13 Kenny De Commer

Leibniz algebras are certain generalizations of Lie algebras. Motivated by the concept of subinvariance in group theory, Schenkman studied properties of subinvariant subalgebras of a Lie algebra. In this paper we define subinvariant…

Rings and Algebras · Mathematics 2020-06-26 Kailash C. Misra , Ernie Stitzinger , Xingjian Yu

We determine when a quasi-isometry between discrete spaces is at bounded distance from a bilipschitz map. From this we prove a geometric version of the Von Neumann conjecture on amenability. We also get some examples in geometric groups…

Group Theory · Mathematics 2009-09-25 Kevin Whyte

The pseudo-amenability of Brandt Banach semigroup algebras is considered.

Functional Analysis · Mathematics 2019-07-30 Maysam Maysami Sadr

In this paper we prove that the Thompson groups $T$ and $V$ are not inner amenable. In particular, their group von Neumann algebras do not have property $\Gamma$. Moreover, we prove that if the reduced group $C^\ast$-algebra of $T$ is…

Operator Algebras · Mathematics 2016-09-19 Uffe Haagerup , Kristian Knudsen Olesen

In this short research note we obtain a reduction theorem for the non-vanishing of the first Hochschild cohomology of block algebras of finite groups with non-trivial defect groups. Along the way we investigate this problem for the blocks…

Representation Theory · Mathematics 2025-04-10 Patrick Serwene , Constantin-Cosmin Todea

In this work we apply Noncommutative Potential Theory to prove (relative) amenability and the (relative) Haagerup Property $(H)$ of von Neumann algebras in terms of the spectral growth of Dirichlet forms. Examples deal with (inclusions of)…

Operator Algebras · Mathematics 2019-10-18 Fabio Cipriani , Jean-Luc Sauvageot

We introduce and study several amenability properties for unitary corepresentations and *-representations of algebraic quantum groups, which may be used to characterize amenability or co-amenability of such groups. As a background for this…

Operator Algebras · Mathematics 2007-05-23 E. Bedos , R. Conti , L. Tuset

We prove several results on the permanence of weak amenability and the Haagerup property for discrete quantum groups. In particular, we improve known facts on free products by allowing amalgamation over a finite quantum subgroup. We also…

Operator Algebras · Mathematics 2014-11-18 Amaury Freslon

We survey some of the progress made recently in the classification of von Neumann algebras arising from countable groups and their measure preserving actions on probability spaces. We emphasize results which provide classes of…

Operator Algebras · Mathematics 2017-12-04 Adrian Ioana

We present coalgebras of some classes of nonassociative algebras whose associator satisfies invariance conditions given by the action of the 3-order symmetric group. Amongst these algebras we find the well-known Vinberg algebras, the…

Rings and Algebras · Mathematics 2007-05-23 Michel Goze , Elisabeth Remm

In this paper we introduce a new class of non-amenable groups denoted by ${\bf NC}_1 \cap {\bf Quot}(\mathcal C_{rss})$ which give rise to $\textit{prime}$ von Neumann algebras. This means that for every $\Gamma \in {\bf NC}_1 \cap {\bf…

Operator Algebras · Mathematics 2017-05-23 Ionut Chifan , Yoshikata Kida , Sujan Pant