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We show that $E$ is a finite graph with no sinks if and only if the Leavitt path algebra $L_R(E)$ is isomorphic to an algebraic Cuntz-Krieger algebra if and only if the $C^*$-algebra $C^*(E)$ is unital and…

Rings and Algebras · Mathematics 2020-01-07 Alireza Nasr-Isfahani

The main aim of the paper is to give a socle theory for Leavitt path algebras of arbitrary graphs. We use both the desingularization process and combinatorial methods to study Morita invariant properties concerning the socle and to…

We study Morita theory of twisted sheaves on $\mu_{n}$-gerbes of line bundles $\mathscr{X}$. In this context, we find explicit equivalent conditions for when two Azumaya algebras on $\mathscr{X}$ are Morita equivalent. Additionally, we…

Algebraic Geometry · Mathematics 2025-07-29 Yeqin Liu , Yu Shen

We give conditions for when continuous orbit equivalence of one-sided shift spaces implies flow equivalence of the associated two-sided shift spaces. Using groupoid techniques, we prove that this is always the case for shifts of finite…

Dynamical Systems · Mathematics 2018-10-08 Toke Meier Carlsen , Søren Eilers , Eduard Ortega , Gunnar Restorff

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

A connected graph can be associated with two distinct evolution algebras. In the first case, the structural matrix is the adjacency matrix of the graph itself. In the second case, the structural matrix is the transition probabilities matrix…

Combinatorics · Mathematics 2024-05-22 Paula Cadavid , Mary Luz Rodiño Montoya , Pablo M. Rodriguez , Sebastian J. Vidal

We introduce a graded homology theory for graded \'etale groupoids. For $\mathbb Z$-graded groupoids, we establish an exact sequence relating the graded zeroth-homology to non-graded one. Specialising to the arbitrary graph groupoids, we…

K-Theory and Homology · Mathematics 2019-01-23 Roozbeh Hazrat , Huanhuan Li

In this paper we show that Leavitt path algebras of weighted graphs and Leavitt path algebras of separated graphs are intimately related. We prove that any Leavitt path algebra $L(E,\omega)$ of a row-finite vertex weighted graph…

Rings and Algebras · Mathematics 2022-05-12 Pere Ara

We describe a method for associating some non-self-adjoint algebras to Mauldin-Williams graphs and we study the Morita equivalence and isomorphism of these algebras. We also investigate the relationship between the Morita equivalence and…

Operator Algebras · Mathematics 2007-05-23 Marius Ionescu

Leavitt path algebras are associated to di(rected )graphs and there is a combinatorial procedure (the reduction algorithm) making the digraph smaller while preserving the Morita type. We can recover the vertices and most of the arrows of…

Rings and Algebras · Mathematics 2025-04-08 Ayten Koç , Murad Özaydın

We initiate the program of extending to higher-rank graphs ($k$-graphs) the geometric classification of directed graph $C^*$-algebras, as completed in the 2016 paper of Eilers, Restorff, Ruiz, and Sorensen [ERRS16]. To be precise, we…

Operator Algebras · Mathematics 2020-06-25 Caleb Eckhardt , Kit Fieldhouse , Daniel Gent , Elizabeth Gillaspy , Ian Gonzales , David Pask

We investigate the use of labelled graphs as a Morita equivalence invariant for inverse semigroups. We construct a labelled graph from a combinatorial inverse semigroup $S$ with $0$ admitting a special set of idempotent $\mathcal{D}$-class…

Group Theory · Mathematics 2025-03-17 Zachary Duah , Stian Du Preez , David Milan , Shreyas Ramamurthy , Lucas Vega

This note extends and strengthens a theorem of Bates that says that row-finite graphs that are strong shift equivalent have Morita equivalent graph C*-algebras. This allows us to ask whether our stronger notion of Morita equivalence does in…

Operator Algebras · Mathematics 2024-05-22 Kevin Aguyar Brix , Pete Gautam

Rings form a bicategory [Rings], with classes of bimodules as horizontal arrows, and bimodule maps as vertical arrows. The notion of Morita equivalence for rings can be translated in terms of bicategories in the following way. Two rings are…

Operator Algebras · Mathematics 2015-06-26 R. M. Brouwer

Let E be an arbitrary directed graph and let K be any field. It is shown that the Leavitt path algebra A of the graph E over the field K is a Zorn ring if and only if the graph E satisfies the Condition (L), that is, every cycle in E has an…

Rings and Algebras · Mathematics 2013-02-20 Kulumani M Rangaswamy

Two unanswered questions in the heart of the theory of Leavitt path algebras are whether Grothendieck group $K_0$ is a complete invariant for the class of unital purely infinite simple algebras and, a weaker question, whether $L_2$ (the…

Rings and Algebras · Mathematics 2023-02-20 Roozbeh Hazrat , Kulumani M. Rangaswamy

The graph groupoids of directed graphs are topologically isomorphic if and only if there is a diagonal-preserving ring *-isomorphism between the Leavitt path algebras.

Rings and Algebras · Mathematics 2016-04-05 Jonathan H. Brown , Lisa Orloff Clark , Astrid an Huef

A connected graph G with at least two vertices is matching covered if each of its edges lies in a perfect matching. We say that an edge e in a matching covered graph G is removable if G-e is matching covered. A pair {e; f} of edges of a…

Combinatorics · Mathematics 2025-06-03 Xiaoling He , Fuliang Lu , Jinxin Xue

It is a conjecture that for the class of Leavitt path algebras associated to finite directed graphs, their graded Grothendieck groups $K_0^{\mathrm{gr}}$ are a complete invariant. For a Leavitt path algebra $L_{\mathsf k}(E)$, with…

Rings and Algebras · Mathematics 2021-06-04 Luiz Gustavo Cordeiro , Daniel Gonçalves , Roozbeh Hazrat

We study harmonic morphisms of graphs as a natural discrete analogue of holomorphic maps between Riemann surfaces. We formulate a graph-theoretic analogue of the classical Riemann-Hurwitz formula, study the functorial maps on Jacobians and…

Combinatorics · Mathematics 2007-07-18 Matthew Baker , Serguei Norine