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Let $\sS$ be a countable, abelian semigroup of continuous surjections on a compact metric space $X$. Corresponding to this dynamical system we associate two operator algebras, the tensor algebra, and the semicrossed product. There is a…

Operator Algebras · Mathematics 2014-10-07 Benton L. Duncan , Justin R. Peters

We propose a new framework that generalizes the parameters of neural network models to $C^*$-algebra-valued ones. $C^*$-algebra is a generalization of the space of complex numbers. A typical example is the space of continuous functions on a…

Machine Learning · Statistics 2022-08-15 Yuka Hashimoto , Zhao Wang , Tomoko Matsui

Supramenability of groups is characterised in terms of invariant measures on locally compact spaces. This opens the door to constructing interesting crossed product C*-algebras for non-supramenable groups. In particular, stable Kirchberg…

Operator Algebras · Mathematics 2013-12-09 Julian Kellerhals , Nicolas Monod , Mikael Rordam

We prove uniqueness of representations of Nica-Toeplitz algebras associated to product systems of $C^*$-correspondences over right LCM semigroups by applying our previous abstract uniqueness results developed for $C^*$-precategories. Our…

Operator Algebras · Mathematics 2019-01-08 Bartosz K. Kwasniewski , Nadia S. Larsen

Let $(A,G,\alpha)$ be a partial dynamical system and let $A\rtimes_{\alpha,r} G$ denote the associated reduced partial crossed product. In this article, we introduce the Haagerup property for partial actions of discrete groups on…

Operator Algebras · Mathematics 2026-04-07 Md Amir Hossain , Chaitanya J. Kulkarni

Let X be an infinite compact metric space with finite covering dimension and let h be a minimal homeomorphism of X. Let A be the associated crossed product C*-algebra. We show that A has tracial rank zero whenever the image of K_0 (A) in…

Operator Algebras · Mathematics 2007-05-23 Huaxin Lin , N. Christopher Phillips

In this paper, we consider $\text{C}^*$-algebras with the ideal property (the ideal property unifies the simple and real rank zero cases). We define two categories related the invariants of the $\text{C}^*$-algebras with the ideal property.…

Operator Algebras · Mathematics 2017-05-30 Kun Wang

A subgroup of an amenable group is amenable. The $C^*$-algebra version of this fact is false. This was first proved by M.-D. Choi who proved that the non-nuclear $C^*$-algebra $C^*_r(\ZZ_2*\ZZ_3)$ is a subalgebra of the nuclear Cuntz…

Operator Algebras · Mathematics 2013-02-26 Guyan Robertson , Tim Steger

We generalize the influential $C^*$-algebraic result of Kawamura-Tomiyama and Archbold-Spielberg for crossed products of discrete transformation groups to the realm of Banach algebras and twisted actions. We prove that topological freeness…

Functional Analysis · Mathematics 2025-03-24 K. Bardadyn , B. K. Kwaśniewski

The paper deals with $C^*$-algebras generated by a net of Hilbert spaces over a partially ordered set. The family of those algebras constitutes a net of $C^*$-algebras over the same set. It is shown that every such an algebra is graded by…

Operator Algebras · Mathematics 2019-05-17 S. A. Grigoryan , E. V. Lipacheva , A. S. Sitdikov

In this paper, we introduce a C*-algebra associated to any substitution (via its Bratteli diagram model). We show that this C*-algebra contains the partial crossed product C*-algebra of the corresponding Bratteli-Vershik system and show…

Operator Algebras · Mathematics 2011-08-24 Daniel Gonçalves , Danilo Royer

We define the full and reduced non-self-adjoint operator algebras associated with \'etale categories and restriction semigroups, answering a question posed by Kudryavtseva and Lawson in \cite{lawson}. Moreover, we define the semicrossed…

Operator Algebras · Mathematics 2024-01-17 Natã Machado , Gilles G. de Castro

Let $\alpha : \Gamma \curvearrowright A$ be an action of a discrete group $\Gamma$ on a unital C*-algebra $A$ by *-automorphisms and let $A \rtimes_{\alpha,\lambda} \Gamma$ denote the corresponding reduced crossed product C*-algebra.…

Operator Algebras · Mathematics 2024-06-04 Matthew Kennedy , Dan Ursu

We introduce the notion of the action of a group on a labeled graph and the quotient object, also a labeled graph. We define a skew product labeled graph and use it to prove a version of the Gross-Tucker theorem for labeled graphs. We then…

Operator Algebras · Mathematics 2013-05-17 Teresa Bates , David Pask , Paulette Willis

We introduce a type of zero-dimensional dynamical system (a pair consisting of a totally disconnected compact metrizable space along with a homeomorphism of that space), which we call "fiberwise essentially minimal", and we prove that the…

Operator Algebras · Mathematics 2021-11-24 Paul Herstedt

We define a broad class of crossed product C*-algebras of the form C(G)xG, where G is a discrete countable amenable residually finite group, and G is a profinite completion of G. We show that they are unital separable simple nuclear…

Operator Algebras · Mathematics 2013-01-22 Stefanos Orfanos

Given a cocycle on a topological quiver by a locally compact group, the author constructs a skew product topological quiver, and determines conditions under which a topological quiver can be identified as a skew product. We investigate the…

Operator Algebras · Mathematics 2024-11-20 Lucas Hall

In arXiv:math/0603621 we introduced the notion of a partial translation $C^*$-algebra for a discrete metric space. Here we demonstrate that several important classical $C^*$-algebras and extensions arise naturally by considering partial…

Operator Algebras · Mathematics 2008-04-04 J. Brodzki , G. A. Niblo , N. J. Wright

To a directed graph $E$ is associated a $C^*$-algebra $C^* (E)$ called a graph $C^*$-algebra. There is a canonical action $\gamma$ of ${\bf T}$ on $C^* (E)$, called the gauge action. In this paper we present necessary and sufficient…

Operator Algebras · Mathematics 2007-05-23 David Pask , Seung-Jai Rho

We describe both the Bunce-Deddens C*-algebras and their Toeplitz versions, as crossed products of commutative C*-algebras by partial automorphisms. In the latter case, the commutative algebra has, as its spectrum, the union of the Cantor…

funct-an · Mathematics 2008-02-03 Ruy Exel
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