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Let $(\A, \alpha)$ and $(\B, \beta)$ be C*-dynamical systems and assume that $\A$ is a separable simple C*-algebra and that $\alpha$ and $\beta$ are *-automorphisms. Then the semicrossed products $\A \times_{\alpha} \bbZ^{+}$ and $\B…

Operator Algebras · Mathematics 2009-02-10 Kenneth R. Davidson , Elias G. Katsoulis

We consider a certain class of unital simple stably finite C^*-algebras which absorb the Jiang-Su algebra Z tensorially. Under a mild assumption, we show that the crossed product of a C^*-algebra in this class by a strongly outer action of…

Operator Algebras · Mathematics 2011-07-05 Hiroki Matui , Yasuhiko Sato

In order to simultaneously generalize matrix rings and group graded crossed products, we introduce category crossed products. For such algebras we describe the center and the commutant of the coefficient ring. We also investigate the…

Rings and Algebras · Mathematics 2008-12-09 Johan Öinert , Patrik Lundström

We provide a reference for basic categorial properties of the categories of (possibly non-unital) $\mathbb{C}$-linear $*$-categories or $C^{*}$-categories, and (not necessarily unit-preserving) functors. Generalizing the classical case of…

Operator Algebras · Mathematics 2021-12-13 Ulrich Bunke

We explore classifiability of crossed products of actions of countable amenable groups on compact, metrizable spaces. It is completely understood when such crossed products are simple, separable, unital, nuclear and satisfy the UCT: these…

Operator Algebras · Mathematics 2024-05-08 Eusebio Gardella , Shirly Geffen , Rafaela Gesing , Grigoris Kopsacheilis , Petr Naryshkin

Let (A,G,\alpha) be a partial dynamical system. We show that there is a bijective correspondence between G-invariant ideals of A and ideals in the partial crossed product A xr G provided the action is exact and residually topologically…

Operator Algebras · Mathematics 2013-05-30 Thierry Giordano , Adam Sierakowski

We introduce a new notion of twisted actions of inverse semigroups and show that they correspond bijectively to certain regular Fell bundles over inverse semigroups, yielding in this way a structure classification of such bundles. These…

Operator Algebras · Mathematics 2014-02-26 Alcides Buss , Ruy Exel

In this paper we work with unital twisted partial actions. We investigate ring theoretic properties of partial crossed products as artinianity, noetherianity, perfect property, semilocalproperty, semiprimary property and we also study the…

Rings and Algebras · Mathematics 2016-03-29 Laerte Bemm , Wagner Cortes

Let $\big((A^{(i)}, G, \alpha^{(i)}), \phi_i\big)_{i \in \mathbb{N}}$ be an inductive sequence of partial dynamical systems. We prove the existence of an induced partial action $\alpha$ of $G$ on the inductive limit $A=\varinjlim A^{(i)}$.…

Operator Algebras · Mathematics 2025-12-03 Md Amir Hossain

In this paper, let $A$ be a unital separable simple infinite dimensional C*-algebra which has uniform property $\Gamma$. Let $\alpha\colon G\to \mathrm{Aut}(A)$ be an action of a finite group which has the weak tracial Rokhlin property.…

Operator Algebras · Mathematics 2025-06-25 Xiaochun Fang , Haotian Tian

We put two C*-algebras together in a noncommutative tensor product using quantum group coactions on them and a bicharacter relating the two quantum groups that act. We describe this twisted tensor product in two equivalent ways. The first…

Operator Algebras · Mathematics 2024-06-25 Ralf Meyer , Sutanu Roy , Stanislaw Lech Woronowicz

It is shown that if A is an AF algebra then a crossed product of A by the integers can be embedded into an AF algebra if and only if the crossed product is stably finite. This equivalence follows from a simple K-theoretic characterization…

funct-an · Mathematics 2007-05-23 Nathanial P. Brown

We introduce a definition of braided tensor product $\operatorname{M}\overline{\boxtimes}\operatorname{N}$ of von Neumann algebras equipped with an action of a quasi-triangular quantum group $\mathbb{G}$ (this includes the case when…

Operator Algebras · Mathematics 2024-12-24 Kenny De Commer , Jacek Krajczok

In this paper we analyse for a $G$-$C^{*}$-algebra $A$ to which extent one can calculate the $K$-theory of the reduced crossed product $K(A\rtimes_{r}G)$ from the $K$-theory spectrum $K(A)$ with the induced $G$-action. We also consider some…

Operator Algebras · Mathematics 2023-11-29 Ulrich Bunke

If $A\otimes _{R, \sigma }V$ and $A\otimes _{P, \nu }W$ are two Brzezi\'nski crossed products and $Q:W\otimes V\rightarrow V\otimes W$ is a linear map satisfying certain properties, we construct a Brzezi\'{n}ski crossed product $A\otimes…

Quantum Algebra · Mathematics 2019-01-15 Leonard Dăuş , Florin Panaite

The $K$-groups of the crossed product of the rotation C*-algebra $A_\theta$ by free and amalgamated products of the cyclic groups $\mathbb Z_n$, for $n=2,3,4,6$, are calculated. The actions here arise from the canonical actions of these…

Operator Algebras · Mathematics 2018-09-26 Sam Walters

For a pair of groups $G, H$ we study pairs of actions $G$ on $H$ and $H$ on $G$ such that these pairs are compatible and non-abelian tensor products $G \otimes H$ are defined.

Group Theory · Mathematics 2017-09-25 V. G. Bardakov , M. V. Neshchadim

We study the relationship between the ultraproduct of a crossed product C*algebra $(A\rtimes_{r}G)^{\omega}$ and the crossed product of an ultraproduct C*algebra $A^{\omega}\rtimes _{r}G$ for a fixed free ultrafilter $\omega$ on…

Operator Algebras · Mathematics 2026-02-24 Zhengyu Fu

Let $G$ be a discrete group. Given unital $G$-$C^*$-algebras $\mathcal{A}$ and $\mathcal{B}$, we give an abstract condition under which every $G$-subalgebra $\mathcal{C}$ of the form $\mathcal{A}\subset \mathcal{C}\subset…

Operator Algebras · Mathematics 2025-06-18 Tattwamasi Amrutam , Yongle Jiang

We introduce the notion of strong Morita equivalence for group actions on locally C*-algebras and prove that the crossed products associated with two strongly Morita equivalent continuous inverse limit actions of a locally compact group G…

Operator Algebras · Mathematics 2007-10-02 Maria Joita