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Related papers: Purely infinite partial crossed products

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Given an n x n integer matrix A whose eigenvalues are strictly greater than 1 in absolute value, let \sigma_A be the transformation of the n-torus T^n=R^n/Z^n defined by \sigma_A(e^{2\pi ix})=e^{2\pi iAx} for x\in R^n. We study the…

Operator Algebras · Mathematics 2010-03-11 Ruy Exel , Astrid an Huef , Iain Raeburn

Given an ample action of an inverse semigroup on a locally compact and Hausdorff topological space, we study the ideal structure of the crossed product algebra associated with it. By developing a theory of induced ideals, we manage to prove…

Operator Algebras · Mathematics 2018-10-02 Paulinho Demeneghi

We consider semicrossed products of the disk algebra with respect to endomorphisms defined by finite Blaschke products. We characterize the Jacobson radical of these operator algebras. Furthermore, in the case the finite Blaschke product is…

Operator Algebras · Mathematics 2019-08-15 Anchalee Khemphet , Justin R. Peters

To a given multivariable C*-dynamical system $(A, \al)$ consisting of *-automorphisms, we associate a family of operator algebras $\alg(A, \al)$, which includes as specific examples the tensor algebra and the semicrossed product. It is…

Operator Algebras · Mathematics 2014-10-06 Evgenios T. A. Kakariadis , Elias G. Katsoulis

We examine crossed product C*-algebras associated with non-minimal free actions of countably infinite discrete abelian groups on the circle, extending the work of Putnam, Schmidt, and Skau. We obtain a large class of unital separable…

Operator Algebras · Mathematics 2026-04-21 Jamie Bell

A subset $X$ of an abelian $G$ is said to be {\em complete} if every element of the subgroup generated by $X$ can be expressed as a nonempty sum of distinct elements from $X$. Let $A\subset \Z_n$ be such that all the elements of $A$ are…

Number Theory · Mathematics 2007-05-23 Y. O. Hamidoune , A. S. Lladó , O. Serra

Let $F$ be a field, let $V$ be a valuation ring of $F$ of arbitrary Krull dimension (rank), let $K$ be a finite Galois extension of $F$ with group $G$, and let $S$ be the integral closure of $V$ in $K$. Let $f:G\times G\mapsto K\setminus…

Rings and Algebras · Mathematics 2014-06-30 John S. Kauta

We study the ideal structure of reduced crossed product of topological dynamical systems of a countable discrete group. More concretely, for a compact Hausdorff space $X$ with an action of a countable discrete group $\Gamma$, we consider…

Operator Algebras · Mathematics 2017-01-13 Takuya Kawabe

We discuss the cyclic homology of crossed product algebras from the Cuntz-Quillen point of view. The periodic cyclic homology of a crossed product algebra $A\rtimes G$ is described in terms of the $G$-action on periodic cyclic bicomplexes…

K-Theory and Homology · Mathematics 2022-10-19 Michael Puschnigg

Starting with a spectral triple on a unital $C^{*}$-algebra $A$ with an action of a discrete group $G$, if the action is uniformly bounded (in a Lipschitz sense) a spectral triple on the reduced crossed product $C^{*}$-algebra $A\rtimes_{r}…

Operator Algebras · Mathematics 2022-08-30 P. Antonini , D. Guido , T. Isola , A. Rubin

We first prove that in a sigma-finite von Neumann factor M, a positive element $a$ with properly infinite range projection R_a is a linear combination of projections with positive coefficients if and only if the essential norm ||a||_e with…

Operator Algebras · Mathematics 2010-07-28 Herbert Halpern , Victor Kaftal , Ping Wong Ng , Shuang Zhang

We prove a result concerning the inclusion of non-trivial invariant ideals inside non-trivial ideals of a twisted crossed product. We will also give results concerning the primeness and simplicity of crossed products of twisted actions of…

Operator Algebras · Mathematics 2007-05-23 Chi-Wai Leung , Chi-Keung Ng

We say that a finitely generated group $G$ has property (QT) if it acts isometrically on a finite product of quasi-trees so that orbit maps are quasi-isometric embeddings. A quasi-tree is a connected graph with path metric quasi-isometric…

Group Theory · Mathematics 2020-10-15 Mladen Bestvina , Kenneth Bromberg , Koji Fujiwara

Given a weak Kac system with duality $(\mathcal{H},V,U)$ arising from regular $\mathrm{C}^{*}$-algebraic locally compact quantum group $(\mathcal{G},\Delta)$, a $\mathrm{C}^{*}$-algebra $A$, and a sufficiently well-behaved coaction…

Operator Algebras · Mathematics 2025-04-17 Matthew Gillespie

We consider Exel's interaction $(V,H)$ over a unital $C^*$-algebra $A$, such that $V(A)$ and $H(A)$ are hereditary subalgebras of $A$. For the associated crossed product, we obtain a uniqueness theorem, ideal lattice description, simplicity…

Operator Algebras · Mathematics 2014-11-27 B. K. Kwaśniewski

We give necessary and sufficient conditions on a row-finite graph E so that the Leavitt path algebra L(E) is purely infinite simple. This result provides the algebraic analog to the corresponding result for the Cuntz-Krieger C$^*$-algebra…

Rings and Algebras · Mathematics 2007-05-23 G. Abrams , G. Aranda Pino

We study the quotients of the Toeplitz C*-algebra of a quasi-lattice ordered group (G,P), which we view as crossed products by a partial actions of G on closed invariant subsets of a totally disconnected compact Hausdorff space, the Nica…

Operator Algebras · Mathematics 2007-05-23 John Crisp , Marcelo Laca

Let $V$ be a M\"{o}bius vertex algebra and $G$ an abelian group of automorphisms of $V$. We construct $P(z)$-tensor product bifunctors for the category of $C_{n}$-cofinite grading-restricted generalized $g$-twisted $V$-modules (without…

Quantum Algebra · Mathematics 2026-01-21 Yi-Zhi Huang

Given a minimal action $G\curvearrowright X$ of a countable group $G$ on a compact space $X$, we prove that if the reduced crossed product $G\ltimes_rC(X)$ is simple, then there exists a point whose stabilizer subgroup has trivial amenable…

Operator Algebras · Mathematics 2026-05-22 Yair Hartman , Mehrdad Kalantar

For $\MvN$ a separable, purely infinite von Neumann algebra with almost periodic weight $\phi$, a decomposition of $\MvN$ as a crossed product of a semifinite von Neumann algebra by a trace--scaling action of a countable abelian group is…

funct-an · Mathematics 2008-02-03 Kenneth J. Dykema