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Related papers: Biexact von Neumann algebras

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We investigate criteria for von-Neumann finiteness and reversibility in some classes of non-associative algebras. We show that all finite-dimensional alternative algebras, as well as all algebras obtained from the real numbers via the…

Rings and Algebras · Mathematics 2020-09-02 Erik Darpö , Patrik Nystedt

We introduce the notion of a bicocycle double cross product (resp. sum) Lie group (resp. Lie algebra), and a bicocycle double cross product bialgebra, generalizing the unified products. On the level of Lie groups the construction yields a…

Quantum Algebra · Mathematics 2022-04-05 O. Esen , P. Guha , S. Sütlü

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

In this paper, we use the tools of nonabelian duality to formulate and prove a far-reaching generalization of the Stone-von Neumann Theorem to modular representations of actions and coactions of locally compact groups on elementary $…

Operator Algebras · Mathematics 2022-06-22 Lucas Hall , Leonard Huang , John Quigg

In \cite{CDD22} we investigated the structure of $\ast$-isomorphisms between von Neumann algebras $L(\Gamma)$ associated with graph product groups $\Gamma$ of flower-shaped graphs and property (T) wreath-like product vertex groups as in…

Operator Algebras · Mathematics 2025-06-03 Ionut Chifan , Michael Davis , Daniel Drimbe

We study the general theory of Frobenius algebras with group actions. These structures arise when one is studying the algebraic structures associated to a geometry stemming from a physical theory with a global finite gauge group, i.e.…

Algebraic Geometry · Mathematics 2007-05-23 Ralph M. Kaufmann

From the mid-1970s, Eberhard Kirchberg undertook a remarkable extensive study of $C^*$-algebras exactness whose applications spread out to many branches of analysis. In this review we focus on the case of groupoid $C^*$-algebras for which…

Operator Algebras · Mathematics 2023-08-10 Claire Anantharaman-Delaroche

We introduce a new equivalence relation on groups, which we call von Neumann equivalence, that is coarser than both measure equivalence and $W^*$-equivalence. We introduce a general procedure for inducing actions in this setting and use…

Operator Algebras · Mathematics 2023-12-29 Ishan Ishan , Jesse Peterson , Lauren Ruth

Expanding on previous work of the author, we initiate the model theoretic study of W$^*$-dynamical systems. We axiomatize continuous weight-preserving group actions of $G$ on von Neumann algebras for $G$ a given locally compact Hausdorff…

Operator Algebras · Mathematics 2025-12-02 Jananan Arulseelan

We characterize in terms of inequalities the possible generalized singular numbers of a product AB of operators A and B having given generalized singular numbers, in an arbitrary finite von Neumann algebra. We also solve the analogous…

Operator Algebras · Mathematics 2016-01-26 Hari Bercovici , Benoit Collins , Ken Dykema , Wing Suet Li

For any injective von Neumann algebra R and any discrete, countable group G, which acts by *-automorphisms on R, we construct an idempotent mapping of an ultra-weakly dense subspace of B(H) onto the reducerd crossed product von Neumann…

Operator Algebras · Mathematics 2020-06-15 Erik Christensen

In this paper we study various rigidity aspects of the von Neumann algebra $L(\Gamma)$ where $\Gamma$ is a graph product group \cite{Gr90} whose underlying graph is a certain cycle of cliques and the vertex groups are the wreath-like…

Operator Algebras · Mathematics 2025-06-03 Ionut Chifan , Michael Davis , Daniel Drimbe

A triple of finite von Neumann algebras $B\subseteq N\subseteq M$ is said to have the relative weak asymptotic homomorphism property if there exists a net of unitary operators $\{u_{\lambda}\}_{\lambda\in \Lambda}$ in $B$ such that…

Operator Algebras · Mathematics 2010-05-19 Junsheng Fang , Mingchu Gao , Roger R. Smith

We study the connection between the condition that the reduced C*-algebra of a finitely presented group is exact and the Novikov conjecture holding. The main result states that if the group is strongly exact in the sense that the inclusion…

Operator Algebras · Mathematics 2007-05-23 Erik Guentner , Jerome Kaminker

We characterize those algebras over a disconnected uniformly complete topological field which are representable as algebras of continuous functions on compact topological spaces, generalizing thus Gelfand duality for non-archimedean normed…

General Topology · Mathematics 2025-10-09 Sebastián Rodríguez , Xavier Caicedo

We present the universal theory of weak crossed biproducts, and we prove that every weak projection of weak bialgebras induces an example of this crossed structure. As an example, we give the construction of a weak projection of a weak…

Quantum Algebra · Mathematics 2009-10-30 J. M. Fernández Vilaboa , R. González Rodríguez , A. B. Rodríguez Raposo

Every unital nonselfadjoint operator algebra possesses canonical and functorial classes of faithful (even completely isometric) Hilbert space representations satisfying a double commutant theorem generalizing von Neumann's classical result.…

Operator Algebras · Mathematics 2007-05-23 David P. Blecher , Baruch Solel

Let g be a Lie bialgebra and let V be a finite-dimensional g-module. We study deformations of the symmetric algebra of V which are equivariant with respect to an action of the quantized enveloping algebra of g. In particular we investigate…

Quantum Algebra · Mathematics 2008-12-09 Sebastian Zwicknagl

We generalize the notion of orbit equivalence to the non-commutative setting by introducing a new equivalence relation on groups, which we call von Neumann orbit equivalence (vNOE). We prove the stability of this equivalence relation under…

Operator Algebras · Mathematics 2026-01-14 Ishan Ishan , Aoran Wu

We introduce a natural generalization of the Haagerup property of a finite von Neumann algebra to an arbitrary von Neumann algebra (with a separable predual) equipped with a normal, semi-finite, faithful weight and prove that this property…

Operator Algebras · Mathematics 2014-11-21 Martijn Caspers , Adam Skalski