scholarly journals SIFAT KEPRIMAAN MODUL SEDERHANA CHEN UNTUK GRAF 𝐴∞

2019 ◽  
Vol 12 (2) ◽  
Author(s):  
Risnawita Risnawita ◽  
Irawati Irawati ◽  
Intan Muchtadi Alamsyah
Keyword(s):  
Directed Graph ◽  
Infinite Sequence ◽  
Line Graph ◽  
Simple Module ◽  
Path Algebra ◽  
Leavitt Path Algebra ◽  
Directed Line ◽  
Simple Modules ◽  
Infinite Path ◽  
Prime Module

Let 𝐾𝐾 be a field, 𝐸𝐸 is a directed graph. Let 𝐴𝐴~ is a directed line graph. Suppose that 𝑉𝑉[𝑝𝑝] is a class of Chen simple module for the Leavitt path algebra (𝐿𝐿𝐾𝐾 (𝐸𝐸)), with [p] being equivalent classes containing an infinite path. An infinite path p is an infinite sequence from the sides of a graph. In this paper it will be shown that 𝑉𝑉[𝑝𝑝]is not a prime module of the Leavitt path algebra for graph 𝐴𝐴∞ .Keywords : Leavitt path algebra, Graph 𝐴𝐴~, Chen simple modules, Prime modules

scholarly journals Group gradations on Leavitt path algebras

2019 ◽  
Vol 19 (09) ◽  
pp. 2050165 ◽  
Author(s):  
Patrik Nystedt ◽  
Johan Öinert
Keyword(s):  
Directed Graph ◽  
Path Algebra ◽  
Graded Rings ◽  
Leavitt Path Algebra ◽  
Arbitrary Group ◽  
Graded Ring ◽  
Identity Component ◽  
Path Algebras ◽  
Leavitt Path Algebras

Given a directed graph [Formula: see text] and an associative unital ring [Formula: see text] one may define the Leavitt path algebra with coefficients in [Formula: see text], denoted by [Formula: see text]. For an arbitrary group [Formula: see text], [Formula: see text] can be viewed as a [Formula: see text]-graded ring. In this paper, we show that [Formula: see text] is always nearly epsilon-strongly [Formula: see text]-graded. We also show that if [Formula: see text] is finite, then [Formula: see text] is epsilon-strongly [Formula: see text]-graded. We present a new proof of Hazrat’s characterization of strongly [Formula: see text]-graded Leavitt path algebras, when [Formula: see text] is finite. Moreover, if [Formula: see text] is row-finite and has no source, then we show that [Formula: see text] is strongly [Formula: see text]-graded if and only if [Formula: see text] has no sink. We also use a result concerning Frobenius epsilon-strongly [Formula: see text]-graded rings, where [Formula: see text] is finite, to obtain criteria which ensure that [Formula: see text] is Frobenius over its identity component.

scholarly journals Strongly graded Leavitt path algebras

2021 ◽  
pp. 2250141
Author(s):  
Patrik Lundström ◽  
Johan Öinert
Keyword(s):  
Recent Result ◽  
Directed Graph ◽  
Path Algebra ◽  
Leavitt Path Algebra ◽  
Unital Ring ◽  
Path Algebras ◽  
Leavitt Path Algebras

Let [Formula: see text] be a unital ring, let [Formula: see text] be a directed graph and recall that the Leavitt path algebra [Formula: see text] carries a natural [Formula: see text]-gradation. We show that [Formula: see text] is strongly [Formula: see text]-graded if and only if [Formula: see text] is row-finite, has no sink, and satisfies Condition (Y). Our result generalizes a recent result by Clark, Hazrat and Rigby, and the proof is short and self-contained.

scholarly journals ALGEBRAIC CUNTZ–KRIEGER ALGEBRAS

2019 ◽  
Vol 109 (1) ◽  
pp. 93-111
Author(s):  
ALIREZA NASR-ISFAHANI
Keyword(s):  
Directed Graph ◽  
Finite Graph ◽  
Path Algebra ◽  
Leavitt Path Algebra ◽  
Group Of Units ◽  
Unital Ring ◽  
Morita Equivalent

We show that a directed graph $E$ is a finite graph with no sinks if and only if, for each commutative unital ring $R$, the Leavitt path algebra $L_{R}(E)$ is isomorphic to an algebraic Cuntz–Krieger algebra if and only if the $C^{\ast }$-algebra $C^{\ast }(E)$ is unital and $\text{rank}(K_{0}(C^{\ast }(E)))=\text{rank}(K_{1}(C^{\ast }(E)))$. Let $k$ be a field and $k^{\times }$ be the group of units of $k$. When $\text{rank}(k^{\times })<\infty$, we show that the Leavitt path algebra $L_{k}(E)$ is isomorphic to an algebraic Cuntz–Krieger algebra if and only if $L_{k}(E)$ is unital and $\text{rank}(K_{1}(L_{k}(E)))=(\text{rank}(k^{\times })+1)\text{rank}(K_{0}(L_{k}(E)))$. We also show that any unital $k$-algebra which is Morita equivalent or stably isomorphic to an algebraic Cuntz–Krieger algebra, is isomorphic to an algebraic Cuntz–Krieger algebra. As a consequence, corners of algebraic Cuntz–Krieger algebras are algebraic Cuntz–Krieger algebras.

scholarly journals Full idempotents in Leavitt path algebras

2019 ◽  
Vol 18 (04) ◽  
pp. 1950062
Author(s):  
Ekrem Emre
Keyword(s):  
Directed Graph ◽  
Sufficient Conditions ◽  
Path Algebra ◽  
Necessary And Sufficient Conditions ◽  
Leavitt Path Algebra ◽  
Path Algebras ◽  
Leavitt Path Algebras ◽  
Necessary And Sufficient

We give necessary and sufficient conditions on a directed graph [Formula: see text] for which the associated Leavit path algebra [Formula: see text] has at least one full idempotent. Also, we define [Formula: see text] sub-graphs of [Formula: see text] and show that [Formula: see text] has at least one full idempotent if and only if there is a sub-graph [Formula: see text] such that the associated Leavitt path algebra [Formula: see text] has at least one full idempotent.

TWO-SIDED CHAIN CONDITIONS IN LEAVITT PATH ALGEBRAS OVER ARBITRARY GRAPHS

2012 ◽  
Vol 11 (03) ◽  
pp. 1250044 ◽  
Author(s):  
GENE ABRAMS ◽  
JASON P. BELL ◽  
PINAR COLAK ◽  
KULUMANI M. RANGASWAMY
Keyword(s):  
Directed Graph ◽  
Path Algebra ◽  
Explicit Description ◽  
Leavitt Path Algebra ◽  
Chain Conditions ◽  
Finite Case ◽  
Path Algebras ◽  
Leavitt Path Algebras ◽  
Arbitrary Graphs

Let E be any directed graph, and K be any field. For any ideal I of the Leavitt path algebra LK(E) we provide an explicit description of a set of generators for I. This description allows us to classify the two-sided noetherian Leavitt path algebras over arbitrary graphs. This extends similar results previously known only in the row-finite case. We provide a number of additional consequences of this description, including an identification of those Leavitt path algebras for which all two-sided ideals are graded. Finally, we classify the two-sided artinian Leavitt path algebras over arbitrary graphs.

scholarly journals SUBSETS OF VERTICES GIVE MORITA EQUIVALENCES OF LEAVITT PATH ALGEBRAS

2017 ◽  
Vol 96 (2) ◽  
pp. 212-222
Author(s):  
LISA ORLOFF CLARK ◽  
ASTRID AN HUEF ◽  
PAREORANGA LUITEN-APIRANA
Keyword(s):  
Directed Graph ◽  
Morita Equivalence ◽  
Path Algebra ◽  
Leavitt Path Algebra ◽  
Algebraic Version ◽  
Morita Equivalent ◽  
Path Algebras ◽  
Leavitt Path Algebras

We show that every subset of vertices of a directed graph$E$gives a Morita equivalence between a subalgebra and an ideal of the associated Leavitt path algebra. We use this observation to prove an algebraic version of a theorem of Crisp and Gow: certain subgraphs of$E$can be contracted to a new graph$G$such that the Leavitt path algebras of$E$and$G$are Morita equivalent. We provide examples to illustrate how desingularising a graph, and in- or out-delaying of a graph, all fit into this setting.

scholarly journals An Algebraic Analogue of a Formula of Knuth

2010 ◽  
Vol DMTCS Proceedings vol. AN,... (Proceedings) ◽  
Author(s):  
Lionel Levine
Keyword(s):  
Directed Graph ◽  
Spanning Trees ◽  
Line Graph ◽  
Torsion Subgroup ◽  
Directed Line ◽  
De Bruijn Graphs ◽  
International Audience ◽  
De Bruijn ◽  
Kautz Graphs ◽  
Sandpile Group

International audience We generalize a theorem of Knuth relating the oriented spanning trees of a directed graph $G$ and its directed line graph $\mathcal{L} G$. The sandpile group is an abelian group associated to a directed graph, whose order is the number of oriented spanning trees rooted at a fixed vertex. In the case when $G$ is regular of degree $k$, we show that the sandpile group of $G$ is isomorphic to the quotient of the sandpile group of $\mathcal{L} G$ by its $k$-torsion subgroup. As a corollary we compute the sandpile groups of two families of graphs widely studied in computer science, the de Bruijn graphs and Kautz graphs. Nous généralisons un théorème de Knuth qui relie les arbres couvrants dirigés d'un graphe orienté $G$ au graphe adjoint orienté $\mathcal{L} G$. On peut associer à tout graphe orienté un groupe abélien appelé groupe du tas de sable, et dont l'ordre est le nombre d'arbres couvrants dirigés enracinés en un sommet fixé. Lorsque $G$ est régulier de degré $k$, nous montrons que le groupe du tas de sable de $G$ est isomorphe au quotient du groupe du tas de sable de $\mathcal{L} G$ par son sous-groupe de $k$-torsion. Comme corollaire, nous déterminons les groupes de tas de sable de deux familles de graphes étudiées en informatique: les graphes de de Bruijn et les graphes de Kautz.

scholarly journals STABLE RANK OF LEAVITT PATH ALGEBRAS OF ARBITRARY GRAPHS

2012 ◽  
Vol 88 (2) ◽  
pp. 206-217 ◽  
Author(s):  
HOSSEIN LARKI ◽  
ABDOLHAMID RIAZI
Keyword(s):  
Directed Graph ◽  
Path Algebra ◽  
Stable Rank ◽  
Leavitt Path Algebra ◽  
Finite Graphs ◽  
Finite Case ◽  
Path Algebras ◽  
Leavitt Path Algebras ◽  
Arbitrary Graphs ◽  
Finite Setting

AbstractThe stable rank of Leavitt path algebras of row-finite graphs was computed by Ara and Pardo. In this paper we extend this to an arbitrary directed graph. In part our computation proceeds as for the row-finite case, but we also use knowledge of the row-finite setting by applying the desingularising method due to Drinen and Tomforde. In particular, we characterise purely infinite simple quotients of a Leavitt path algebra.

scholarly journals Prüfer modules over Leavitt path algebras

2019 ◽  
Vol 18 (08) ◽  
pp. 1950154
Author(s):  
Gene Abrams ◽  
Francesca Mantese ◽  
Alberto Tonolo
Keyword(s):  
Simple Module ◽  
Finite Graph ◽  
Path Algebra ◽  
Injective Hull ◽  
Closed Path ◽  
Leavitt Path Algebra ◽  
Path Algebras ◽  
Simple Factor ◽  
Leavitt Path Algebras

Let [Formula: see text] denote the Leavitt path algebra associated to the finite graph [Formula: see text] and field [Formula: see text]. For any closed path [Formula: see text] in [Formula: see text], we define and investigate the uniserial, artinian, non-Noetherian left [Formula: see text]-module [Formula: see text]. The unique simple factor of each proper submodule of [Formula: see text] is isomorphic to the Chen simple module [Formula: see text]. In our main result, we classify those closed paths [Formula: see text] for which [Formula: see text] is injective. In this situation, [Formula: see text] is the injective hull of [Formula: see text].

scholarly journals A Note on the Critical Group of a Line Graph

10.37236/611 ◽  
2011 ◽  
Vol 18 (1) ◽  
Author(s):  
David Perkinson ◽  
Nick Salter ◽  
Tianyuan Xu
Keyword(s):  
Directed Graph ◽  
Line Graph ◽  
Critical Group ◽  
Directed Line

This note answers a question posed by Levine. The main result shows that under certain circumstances a critical group of a directed graph is the quotient of a critical group of its directed line graph.

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