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Related papers: The ordered K_0-group of a graph C*-algebra

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We generalize the Li-Yang notion of self-similar $k$-graph $(G,\Lambda)$ and its $C^*$-algebra $\mathcal{O}_{G,\Lambda}$ to any finitely aligned $k$-graph $\Lambda$. We then introduce an inverse semigroup model for $\mathcal{O}_{G,\Lambda}$…

Operator Algebras · Mathematics 2024-11-22 Hossein Larki

We investigate conditions on a graph $C^*$-algebra for the existence of a faithful semifinite trace. Using such a trace and the natural gauge action of the circle on the graph algebra, we construct a smooth $(1,\infty)$-summable semfinite…

Functional Analysis · Mathematics 2007-05-23 David Pask , Adam Rennie

Given a simple, acyclic dimension group $G_{0}$ and countable, torsion-free, abelian group $G_{1}$, we construct a minimal, amenable, \'{e}tale equivalence relation $R$ on a Cantor set whose associated groupoid $C^{*}$-algebra, $C^{*}(R)$,…

Operator Algebras · Mathematics 2017-09-26 Ian F. Putnam

We compare the K-theory and K-homology of the well known CAR algebra. While the $K_0$ group is infinitely generated, we shows that it pairs identically to zero with even Fredholm modules over the algebra. We show further that in fact the…

Operator Algebras · Mathematics 2016-09-07 Tom Hadfield

We give an algorithm to compute the $K$-groups of the crossed product by the flip automorphism for a nuclear C$^*$-algebra satisfying the UCT.

Operator Algebras · Mathematics 2017-02-08 Masaki Izumi

We give an example of an exact, stably finite, simple. separable C*-algebra D which is not isomorphic to its opposite algebra. Moreover, D has the following additional properties. It is stably finite, approximately divisible, has real rank…

Operator Algebras · Mathematics 2014-01-22 N. Christopher Phillips , Maria Grazia Viola

Let $C^*(E)$ be the graph $C^*$-algebra associated to a graph E and let J be a gauge invariant ideal in $C^*(E)$. We compute the cyclic six-term exact sequence in $K$-theory of the associated extension in terms of the adjacency matrix…

Operator Algebras · Mathematics 2012-11-20 Toke M. Carlsen , Søren Eilers , Mark Tomforde

In this paper we study the part of the $K$-theory of the reduced $C^*$-algebra arising from torsion elements of the group, and in particular we study the pairing of $K$-theory with traces and when traces can detect certain $K$-theory…

K-Theory and Homology · Mathematics 2016-09-30 Sherry Gong

Inspired by results for graph $C^*$-algebras, we investigate connections between the ideal structure of an inverse semigroup $S$ and that of its tight $C^*$-algebra by relating ideals in $S$ to certain open invariant sets in the associated…

Operator Algebras · Mathematics 2019-01-29 Scott M. LaLonde , David Milan , Jamie Scott

A class of $C^*$-algebras, to be called those of generalized tracial rank one, is introduced, and classified by the Elliott invariant. A second class of unital simple separable amenable $C^*$-algebras, those whose tensor products with…

Operator Algebras · Mathematics 2020-12-08 Guihua Gong , Huaxin Lin , Zhuang Niu

We appeal to results from combinatorial random matrix theory to deduce that various random graph $\mathrm{C}^*$-algebras are asymptotically almost surely Kirchberg algebras with trivial $K_1$. This in particular implies that, with high…

Operator Algebras · Mathematics 2025-05-22 Bhishan Jacelon , Igor Khavkine

We introduce the fundamental group ${\mathcal F}(A)$ of a unital simple $C^*$-algebra $A$ with a unique normalized trace. We compute fundamental groups ${\mathcal F}(A)$ of several nuclear or non-nuclear $C^*$-algebras $A$. K-theoretical…

Operator Algebras · Mathematics 2009-04-08 Norio Nawata , Yasuo Watatani

Order unit property of a positive element in a $C^{*}$-algebra is defined. It is proved that precisely projections satisfy this order theoretic property. This way, unital hereditary $C^{*}$-subalgebras of a $C^{*}$-algebra are…

Operator Algebras · Mathematics 2007-05-23 Anil K. Karn

In this paper we show how to produce a large number of representations of a graph C*-algebra in the space of the bounded linear operators in $L^2(X,\mu)$. These representations are very concrete and, in the case of graphs that satisfy…

Operator Algebras · Mathematics 2014-07-04 Danilo Royer , Daniel Gonçalves

K-theory and Ext are computed for the C*-algebra C*(E) of any countable directed graph E. The results generalize the K-theory computations of Raeburn and Szymanski and the Ext computations of Tomforde for row-finite graphs. As a…

Operator Algebras · Mathematics 2007-05-23 D. Drinen , M. Tomforde

We shall consider a locally compact groupoid endowed with a Haar system and having proper orbit space. We shall construct a groupoid C*-algebra which is independent of the Haar system (up to a *-isomorphism).

Operator Algebras · Mathematics 2007-05-23 Madalina Roxana Buneci

This survey reports on current progress of programs to classify graph C*-algebras and Leavitt path algebras up to Morita equivalence using K-theory. Beginning with an overview and some history, we trace the development of the classification…

Operator Algebras · Mathematics 2016-03-22 Mark Tomforde

Let $(G, \Lambda)$ be a self-similar $k$-graph with a possibly infinite vertex set $\Lambda^0$. We associate a universal C*-algebra $\mathcal{O}_{G,\Lambda}$ to $(G,\Lambda)$. The main purpose of this paper is to investigate the ideal…

Operator Algebras · Mathematics 2019-06-26 Hui Li , Dilian Yang

For a Lie groupoid there is an analytic index morphism which takes values in the $K-$theory of the $C^*$-algebra associated to the groupoid. This is a good invariant but extracting numerical invariants from it, with the existent tools, is…

K-Theory and Homology · Mathematics 2007-05-23 Paulo Carrillo Rouse

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