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We provide a complete characterization of theories of tracial von Neumann algebras that admit quantifier elimination. We also show that the theory of a separable tracial von Neumann algebra $\mathcal{N}$ is never model complete if its…

Operator Algebras · Mathematics 2025-07-09 Ilijas Farah , David Jekel , Jennifer Pi

Compact matrix quantum groups act naturally on Cuntz algebras. The first author isolated certain conditions under which the fixed point algebras under this action are Kirchberg algebras. Hence they are completely determined by their…

Operator Algebras · Mathematics 2016-10-04 Olivier Gabriel , Moritz Weber

The Baum-Connes map for finitely generated free abelian groups is a K-theoretic analogue of the Fourier-Mukai transform from algebraic geometry. We describe this K-theoretic transform in the language of topological correspondences, and…

K-Theory and Homology · Mathematics 2020-07-29 Heath Emerson , Dan Hudson

Let $(H_{\mathbf{R}}, U_t)$ be any strongly continuous orthogonal representation of $\mathbf{R}$ on a real (separable) Hilbert space $H_{\mathbf{R}}$. For any $q\in (-1,1)$, we denote by $\Gamma_q(H_{\mathbf{R}},U_t)^{\prime\prime}$ the…

Operator Algebras · Mathematics 2021-02-01 Cyril Houdayer , Yusuke Isono

We describe a universal factorization for a functor with values in finite-dimensional measured algebras. More precisely we contruct the quantum automorphism group of this functor. This general recontruction result allows us to recapture a…

Quantum Algebra · Mathematics 2007-05-23 Julien Bichon

The constructions of free subproducts of von Neumann algebras and free scaled products are introduced, and results about them are proved, including rescaling results and results about free trade in free scaled products.

Operator Algebras · Mathematics 2007-05-23 Ken Dykema

Quantum bialgebras derivable from Uq(sl2) which contain idempotents and von Neumann regular Cartan-like generators are introduced and investigated. Various types of antipodes (invertible and von Neumann regular) on these bialgebras are…

Quantum Algebra · Mathematics 2014-11-18 Steven Duplij , Sergey Sinel'shchikov

We study the equivalence relation $R_N$ generated by the (non-free) action of the generalized Thompson group $F_N$ on the unit interval. We show that this relation is a standard, quasipreserving ergodic equivalence relation. Using results…

Operator Algebras · Mathematics 2007-05-23 Dorin Dutkay , Gabriel Picioroaga

Let G be a group and let K be a field of characteristic zero. We shall prove that KG can be embedded into a von Neumann unit-regular ring. In the course of the proof, we shall obtain a result relevant to the Atiyah conjecture.

Rings and Algebras · Mathematics 2007-08-17 Peter A. Linnell

Let A be a maximal abelian self-adjoint subalgebra (masa) in a type II_1 factor M acting via standard representation on L^2(M). The abelian von Neumann algebra A generated by A and JAJ has a type I commutant which contains the projection…

Operator Algebras · Mathematics 2007-05-23 Ken Dykema , Allan Sinclair , Roger Smith

In the first part, the second quantization procedure and the free Bosonic scalar field will be introduced, and the axioms for quantum fields and nets of observable algebras will be discussed. The second part is mainly devoted to an…

Operator Algebras · Mathematics 2011-02-01 Daniele Guido

We prove the first rigidity and classification theorems for crossed product von Neumann algebras given by actions of non-discrete, locally compact groups. We prove that for arbitrary free probability measure preserving actions of connected…

Operator Algebras · Mathematics 2018-07-20 Arnaud Brothier , Tobe Deprez , Stefaan Vaes

We study the two-sided Guionnet-Jones-Shlyakhtenko construction applied to the group planar algebra $P(\mathcal{G})$ of a finite non-trivial group $\mathcal{G}$. This produces a sequence of von Neumann algebras $M^k$ for $k \geq 0$ with no…

Operator Algebras · Mathematics 2025-10-02 R Jayakumar

We obtain a Lie theoretic intrinsic characterization of the connected and simply connected solvable Lie groups whose regular representation is a factor representation. When this is the case, the corresponding von Neumann algebras are…

Representation Theory · Mathematics 2024-05-15 Ingrid Beltita , Daniel Beltita

We study group algebras for compact groups in the category of real and complex weakly complete vector spaces. We also show that the group algebra is a quotient of the weakly complete universal enveloping algebra of the Lie algebra of the…

Group Theory · Mathematics 2019-11-18 Karl Heinrich Hofmann , Linus Kramer

Using Godement mean on the Fourier-Stieltjes algebra of a locally compact quantum group we obtain strong separation results for quantum positive-definite functions associated to a subclass of representations, strengthening for example the…

Operator Algebras · Mathematics 2025-01-28 Jacek Krajczok , Adam Skalski

Let $M$ be a finite von Neumann algebra (resp. a type II$_{1}$ factor) and let $N\subset M$ be a II$_{1}$ factor (resp. $N\subset M$ have an atomic part). We prove that the inclusion $N\subset M$ is amenable implies the identity map on $M$…

Operator Algebras · Mathematics 2018-09-05 Xiaoyan Zhou , Junsheng Fang

Recently, we have shown that von Neumann algebras form a model for Selinger and Valiron's quantum lambda calculus. In this paper, we explain our choice of interpretation of the duplicability operator "!" by studying those von Neumann…

Operator Algebras · Mathematics 2019-03-08 Kenta Cho , Abraham A. Westerbaan

The main result of this paper is a generalization of Popa's free independence result for subalgebras of ultraproduct ${\rm II_1}$ factors [Po95] to the framework of ultraproduct von Neumann algebras $(M^\omega, \varphi^\omega)$ where $(M,…

Operator Algebras · Mathematics 2015-07-29 Cyril Houdayer , Yusuke Isono

We give some natural conditions on actions of discrete countable groups on abelian locally compact groups of Lie type that imply factoriality of the group von Neumann algebras of their semidirect products. This allows us to give a fairly…

Operator Algebras · Mathematics 2025-11-18 Soham Chakraborty , Chinmay Tamhankar