English
Related papers

Related papers: Strongly graded groupoid and directed graph algebr…

200 papers

Hazrat gave a K-theoretic invariant for Leavitt path algebras as graded algebras. Hazrat conjectured that this invariant classifies Leavitt path algebras up to graded isomorphism, and proved the conjecture in some cases. In this paper, we…

Rings and Algebras · Mathematics 2014-05-05 P. Ara , E. Pardo

We construct a weak conditional expectation from the section C*-algebra of a Fell bundle over a unital inverse semigroup to its unit fibre. We use this to define the reduced C*-algebra of the Fell bundle. We study when the reduced…

Operator Algebras · Mathematics 2019-04-30 Alcides Buss , Ruy Exel , Ralf Meyer

For a postive integer $n$ and a subset $S$ of $\mathbb{Z}_n$, let $\left\langle S\right\rangle =\mathbb{Z}_n$, and $w:S\rightarrow\mathbb{N}$ be a function. The weighted Cayley graph of the cyclic group $\mathbb{Z}_n$ with respect to $S$…

Rings and Algebras · Mathematics 2020-01-01 Mohan. R

Leavitt inverse semigroups of directed finite graphs are related to Leavitt graph algebras of (directed) graphs. Leavitt path algebras of graphs have the natural $\mathbb Z$-grading via the length of paths in graphs. We consider the…

Rings and Algebras · Mathematics 2024-12-13 Huanhuan Li , Zongchao Li , Zhengpan Wang

We develop methods for computing graded K-theory of C*-algebras as defined in terms of Kasparov theory. We establish graded versions of Pimsner's six-term sequences for graded Hilbert bimodules whose left action is injective and by…

Operator Algebras · Mathematics 2017-06-05 Alex Kumjian , David Pask , Aidan Sims

We introduce a family of $C^*$-correspondences $X_\alpha$ naturally associated to every ordinal graph $\Lambda$. When $\Lambda$ is a directed graph, $X_0$ is isomorphic to the usual $C^*$-correspondence associated to a graph. We show that…

Operator Algebras · Mathematics 2026-02-18 Benjamin Jones

We show that semigroup C*-algebras are groupoid C*-algebras.

Operator Algebras · Mathematics 2019-06-14 Hui Li

We show that every groupoid C*-algebra is isomorphic to its opposite, and deduce that there exist C*-algebras that are not stably isomorphic to groupoid C*-algebras, though many of them are stably isomorphic to twisted groupoid C*-algebras.…

Operator Algebras · Mathematics 2017-08-15 Alcides Buss , Aidan Sims

For any row-finite graph $E$ and any field $K$ we construct the {\its Leavitt path algebra} $L(E)$ having coefficients in $K$. When $K$ is the field of complex numbers, then $L(E)$ is the algebraic analog of the Cuntz Krieger algebra…

Rings and Algebras · Mathematics 2007-05-23 G. Abrams , G. Aranda Pino

We show how to construct a graded locally compact Hausdorff \'etale groupoid from a C*-algebra carrying a coaction of a discrete group, together with a suitable abelian subalgebra. We call this groupoid the extended Weyl groupoid. When the…

Operator Algebras · Mathematics 2022-07-18 Toke Meier Carlsen , Efren Ruiz , Aidan Sims , Mark Tomforde

We prove directly that if E is a directed graph in which every cycle has an entrance, then there exists a C*-algebra which is co-universal for Toeplitz-Cuntz-Krieger E-families. In particular, our proof does not invoke ideal-structure…

Operator Algebras · Mathematics 2010-01-13 Aidan Sims , Samuel B. G. Webster

From a suitable groupoid G, we show how to construct an amenable principal groupoid whose C*-algebra is a Kirchberg algebra which is KK-equivalent to C*(G). Using this construction, we show by example that many UCT Kirchberg algebras can be…

Operator Algebras · Mathematics 2016-02-29 Jonathan H. Brown , Lisa Orloff Clark , Adam Sierakowski , Aidan Sims

Suppose G is a second countable, locally compact, Hausdorff, principal groupoid with a fixed left Haar system. We define a notion of integrability for groupoids, and show G is integrable if and only if the groupoid C*-algebra C*(G) has…

Operator Algebras · Mathematics 2007-05-23 Lisa Orloff Clark , Astrid an Huef

There are two established gradings on Leavitt path algebras associated with ultragraphs, namely the grading by the integers group and the grading by the free group on the edges. In this paper, we characterize properties of these gradings in…

Rings and Algebras · Mathematics 2021-07-06 Daniel Gonçalves , Danilo Royer

Given a directed graph $E$ and a labeling $\mathcal{L}$, one forms the labelled graph $C^*$-algebra by taking a weakly left--resolving labelled space $(E, \mathcal{L}, \mathcal{B})$ and considering a universal generating family of partial…

Operator Algebras · Mathematics 2019-07-16 Menassie Ephrem

We show that certain extensions of classifiable C*-algebra are strongly classified by the associated six-term exact sequence in K-theory together with the positive cone of K_{0}-groups of the ideal and quotient. We apply our result to give…

Operator Algebras · Mathematics 2013-02-01 Soren Eilers , Gunnar Restorff , Efren Ruiz

A $\lambda$-graph system is a labeled Bratteli diagram with certain additional structure, which presents a subshift. The class of the $C^*$-algebras $\mathcal{O}_{\frak L}$ associated with the $\lambda$-graph systems is a generalized class…

Operator Algebras · Mathematics 2024-05-29 Kengo Matsumoto

In sharp contrast to the Abrams-Rangaswamy Theorem that the only von Neumann regular Leavitt path algebras are exactly those associated to acyclic graphs, here we prove that the Leavitt path algebra of any arbitrary graph is a graded von…

Rings and Algebras · Mathematics 2013-05-08 Roozbeh Hazrat

Following our previous works on $C^*$-graph algebras and the associated Cuntz-Krieger graph families, in this paper we will try to have a look at the colored version of these structures and to see what a $C^*$-colored graph algebra might…

Operator Algebras · Mathematics 2025-04-25 Farrokh Razavinia

Given any simple biorientable graph it is shown that there exists a weak {*}-Hopf algebra constructed on the vector space of graded endomorphisms of essential paths on the graph. This construction is based on a direct sum decomposition of…

Quantum Algebra · Mathematics 2015-03-17 R. Trinchero
‹ Prev 1 4 5 6 7 8 10 Next ›