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Related papers: The RFD property for graph $C^*$-algebras

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A Hilbert $C^*$-quad module of finite type has a multi structure of Hilbert $C^*$-bimodules with two finite bases. We will construct a $C^*$-algebra from a Hilbert $C^*$-quad module of finite type and prove its universality subject to…

Operator Algebras · Mathematics 2013-10-01 Kengo Matsumoto

We give a construction of a family of locally finite residually finite groups with just-infinite C*-algebra. This answers a question from [2]. Additionally, we show that residually finite groups of finite exponent are never just-infinite.

Operator Algebras · Mathematics 2016-06-27 V. Belyaev , R. Grigorchuk , P. Shumyatsky

In this paper, we use the theory of Riordan matrices to introduce the notion of a Riordan graph. The Riordan graphs are a far-reaching generalization of the well known and well studied Pascal graphs and Toeplitz graphs, and also some other…

Combinatorics · Mathematics 2019-04-16 Gi-Sang Cheon , Ji-Hwan Jung , Sergey Kitaev , Seyed Ahmad Mojallal

We obtain a characterization in terms of dynamical systems of those r-discrete groupoids for which the groupoid C*-algebra is approximately finite-dimensional (AF). These ideas are then used to compute the K-theory for AF algebras by…

Operator Algebras · Mathematics 2007-05-23 Justin R. Peters , Ryan J. Zerr

A set of vertices $S$ \emph{resolves} a graph $G$ if every vertex is uniquely determined by its vector of distances to the vertices in $S$. The \emph{metric dimension} of a graph $G$ is the minimum cardinality of a resolving set. In this…

Combinatorics · Mathematics 2009-05-01 J. Cáceres , C. Hernando , M. Mora , M. L. Puertas , I. M. Pelayo

We give a sufficient condition on totally disconnected topological graphs such that their associated topological graph algebras are purely infinite.

Operator Algebras · Mathematics 2017-03-31 Hui Li

We call a finite-dimensional K-algebra A geometrically irreducible if for all d all connected components of the affine scheme of d-dimensional A-modules are irreducible. We prove that a geometrically irreducible algebra with exactly two…

Representation Theory · Mathematics 2018-01-12 Grzegorz Bobiński , Jan Schröer

Let $G$ be a Hausdorff, \'etale groupoid that is minimal and topologically principal. We show that $C^*_r(G)$ is purely infinite simple if and only if all the nonzero positive elements of $C_0(G^0)$ are infinite in $C_r^*(G)$. If $G$ is a…

Operator Algebras · Mathematics 2014-08-13 Jonathan Brown , Lisa Orloff Clark , Adam Sierakowski

In this paper we generalize the notion of a $k$-graph into (countable) infinite rank. We then define our $C^*$-algebra in a similar way as in $k$-graph $C^*$-algebras. With this construction we are able to find analogues to the Gauge…

Operator Algebras · Mathematics 2022-02-18 Tim Schenkel

We develop the theory of ``branch algebras'', which are infinite-dimensional associative algebras that are isomorphic, up to taking subrings of finite codimension, to a matrix ring over themselves. The main examples come from groups acting…

Rings and Algebras · Mathematics 2009-11-27 Laurent Bartholdi

We say that a vertex or edge colouring of a graph is distinguishing if the only automorphism that preserves this colouring is the identity. A (proper) distinguishing colouring is irreducible if there is no possibility of merging two…

Combinatorics · Mathematics 2026-02-18 Marcin Stawiski

In the paper I considered linear and antilinear mappings of finite dimensional algebra over complex field, as well I considered involution. I considered also an example of $C^*$\Hyph algebra.

Rings and Algebras · Mathematics 2011-05-24 Aleks Kleyn

We show that an automorphism of a unital AF C*-algebra with the approximate Rohlin property has the Rohlin property. This generalizes a result of Kishimoto. Using this we show that the shift automorphism on the bilateral C*-algebra…

Functional Analysis · Mathematics 2007-05-23 Charles Holton

This article investigates the properties of order-divisor graphs associated with finite groups. An order-divisor graph of a finite group is an undirected graph in which the set of vertices includes all elements of the group, and two…

Group Theory · Mathematics 2024-08-30 Shafiq ur Rehman , Raheela Tahir , Farhat Noor

A class $\mathcal{G}$ of graphs is hereditary if it is closed under taking induced subgraphs. We investigate the edge-add class, $\mathcal{G}^{\mathrm{add}}$, consisting of graphs that can be made members of $\mathcal{G}$ by adding at most…

Combinatorics · Mathematics 2026-04-10 Jagdeep Singh , Vaidy Sivaraman

We present a novel approach to the representation theory of finite dimensional algebras motivated by the emerging theory of graph limits. We introduce the rank spectrum of a finite dimensional algebra $R$ over a finite field. The elements…

Representation Theory · Mathematics 2016-03-15 Gabor Elek

Kumjian and Pask introduced an aperiodicity condition for higher rank graphs. We present a detailed analysis of when this occurs in certain rank 2 graphs. When the algebra is aperiodic, we give another proof of the simplicity of…

Operator Algebras · Mathematics 2019-08-15 Kenneth R. Davidson , Dilian Yang

An infinite matroid is graphic if all of its finite minors are graphic and the intersection of any circuit with any cocircuit is finite. We show that a matroid is graphic if and only if it can be represented by a graph-like topological…

Combinatorics · Mathematics 2013-09-17 Nathan Bowler , Johannes Carmesin , Robin Christian

Let A be a C*-algebra. It is shown that A is an AW*-algebra if, and only if, each maximal abelian self--adjoint subalgebra of A is monotone complete. An analogous result is proved for Rickart C*-algebras; a C*-algebra is a Rickart…

Operator Algebras · Mathematics 2015-01-13 Kazuyuki Saitô , J. D. Maitland Wright

An extension of algebras is a homomorphism of algebras preserving identities. We use extensions of algebras to study the finitistic dimension conjecture over Artin algebras. Let $f: B \to A$ be an extension of Artin algebras. We denote by…

Rings and Algebras · Mathematics 2018-03-01 Shufeng Guo