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We show that important structural properties of C*-algebras and the multiplicity numbers of representations are preserved under Morita equivalence.

Operator Algebras · Mathematics 2007-05-23 Astrid an Huef , Iain Raeburn , Dana P. Williams

We consider the $C^*$-algebra generated by finitely many annihilation operators acting on the weakly monotone Fock space, and we call it weakly monotone $C^*$-algebra. We give an abstract representation for this algebra, showing that it is…

Operator Algebras · Mathematics 2025-01-22 Maria Elena Griseta , Janusz Wysoczański

We pose a conjecture on the K-theory of the self-similar $k$-graph C*-algebra of a standard product of odometers. We generalize the C*-algebra $\mathcal{Q}_S$ to any subset of $\mathbb{N}^\times \setminus \{1\}$ and then realize it as the…

Operator Algebras · Mathematics 2020-03-24 Hui Li

We consider conditions on a $k$-graph $\Lambda$, a semigroup $S$ and a functor $\eta : \Lambda \to S$ which ensure that the $C^*$-algebra of the skew-product graph $\Lambda \times_\eta S$ is simple. Our results allow give some necessary and…

Operator Algebras · Mathematics 2013-06-27 Ben Maloney , David Pask

In this paper we describe a new method of defining C*-algebras from oriented combinatorial data, thereby generalizing the constructions of algebras from directed graphs, higher-rank graphs, and ordered groups. We show that only the most…

Operator Algebras · Mathematics 2014-05-21 Jack Spielberg

If $E$ is a not-necessarily row-finite graph, such that each vertex of $E$ emits at most countably many edges, then a {\it desingularization} $F$ of $E$ can be constructed (see e.g. (1) G. Abrams, G. Aranda Pino, Leavitt path algebras of…

Rings and Algebras · Mathematics 2011-01-05 Gene Abrams , Kulumani M. Rangaswamy

An oriented graph is a directed graph without any cycle of length at most 2. To push a vertex of a directed graph is to reverse the orientation of the arcs incident to that vertex. Klostermeyer and MacGillivray defined push graphs which are…

Discrete Mathematics · Computer Science 2015-08-31 Sagnik Sen

To a graph $\Gamma$ one can associate a C^*-algebra $C^*(\Gamma)$ generated by isometries. Such $C^*$-algebras were studied recently by Crisp and Laca. They are a special case of the Toeplitz C^*-algebras $\mathcal{T}(G, P)$ associated to…

Operator Algebras · Mathematics 2007-11-07 Nikolay A. Ivanov

Let $K$ be a compact metric space and let $\varphi: K \to K$ be continuous. We study C*-algebra $\mathcal{MC}_\varphi$ generated by all multiplication operators by continuous functions on $K$ and a composition operator $C_\varphi$ induced…

Operator Algebras · Mathematics 2019-11-26 Hiroyasu Hamada

I show how to associate a Clifford algebra to a graph. I describe the structure of these Clifford graph algebras and provide many examples and pictures. I describe which graphs correspond to isomorphic Clifford algebras and also discuss…

Combinatorics · Mathematics 2013-06-25 Tanya Khovanova

We introduce a divisibility-type condition for directed graphs that is necessary for $\mathcal{Z}$-stability of the corresponding graph $C^*$-algebra. We prove that this condition is sufficient if either the graph $E$ has no cycles or the…

Operator Algebras · Mathematics 2025-11-05 Gregory Faurot

Let E be a row-finite directed graph. We prove that there exists a C*-algebra C*_{min}(E) with the following co-universal property: given any C*-algebra B generated by a Toeplitz-Cuntz-Krieger E-family in which all the vertex projections…

Operator Algebras · Mathematics 2008-09-16 Aidan Sims

Quantum symmetry of graph $C^{*}$-algebras has been studied, under the consideration of different formulations, in the past few years. It is already known that the compact quantum group $(\underbrace{C(S^{1})*C(S^{1})*\cdots…

Operator Algebras · Mathematics 2024-08-08 Ujjal Karmakar , Arnab Mandal

Let $G$ be a finite graph and $\kappa(G)$ the vertex connectivity of $G$. A chordal graph $G$ is called chordal$^*$ if no vertex of $G$ is adjacent to all other vertices of $G$. Using the syzygy theory in commutative algebra, it is proved…

Combinatorics · Mathematics 2025-02-12 Tài Huy Hà , Takayuki Hibi

A meteor graph is a connected graph with no sources and sinks consisting of two disjoint cycles and the paths connecting these cycles. We prove that two meteor graphs are shift equivalent if and only if they are strongly shift equivalent,…

Rings and Algebras · Mathematics 2023-04-14 L. G. Cordeiro , E. Gillaspy , D. Goncalves , R. Hazrat

In this paper, we discuss a method of constructing separable representations of the $C^*$-algebras associated to strongly connected row-finite $k$-graphs $\Lambda$. We begin by giving an alternative characterization of the…

Operator Algebras · Mathematics 2018-03-26 Carla Farsi , Elizabeth Gillaspy , Palle E. T. Jorgensen , Sooran Kang , Judith Packer

It is well known that "bad" quotient spaces (typically: non-Hausdorff) can be studied by associating to them the groupoid C*-algebra of an equivalence relation, that in the "nice" cases is Morita equivalent to the C*-algebra of continuous…

Operator Algebras · Mathematics 2022-07-13 Francesco D'Andrea , Giovanni Landi , Fedele Lizzi

We show that for a sofic shift Lambda, Matsumoto's C*-algebra O_Lambda is isomorphic to the Cuntz-Krieger algebra of the left Krieger cover graph of Lambda.

Operator Algebras · Mathematics 2007-05-23 Toke Meier Carlsen

It is proved that classifiable simple separable nuclear purely infinite C*-algebras having finitely generated K-theory and torsion-free K_1 are semiprojective. This is accomplished by exhibiting these algebras as C*-algebras of infinite…

Operator Algebras · Mathematics 2007-05-23 Jack Spielberg

An introduction to Leavitt path algebras of arbitrary directed graphs is presented, and direct limit techniques are developed, with which many results that had previously been proved for countable graphs can be extended to uncountable ones.…

Rings and Algebras · Mathematics 2007-12-18 K. R. Goodearl