English
Related papers

Related papers: Williams' Conjecture holds for meteor graphs

200 papers

We say a graph $G$ has a Hamiltonian path if it has a path containing all vertices of $G$. For a graph $G$, let $\sigma_2(G)$ denote the minimum degree sum of two nonadjacent vertices of $G$; restrictions on $\sigma_2(G)$ are known as…

Combinatorics · Mathematics 2020-01-07 Ilkyoo Choi , Jinha Kim

We explicitly describe two-sided ideals in Leavitt path algebras associated with a row-finite graph. Our main result is that any two-sided ideal $I$ of a Leavitt path algebra associated with a row-finite graph is generated by elements of…

Rings and Algebras · Mathematics 2010-03-16 Pinar Colak

We generalize the classification result of Restorff on Cuntz-Krieger algebras to cover all unital graph C*-algebras with real rank zero, showing that Morita equivalence in this case is determined by ordered, filtered K-theory as conjectured…

Operator Algebras · Mathematics 2015-07-09 Søren Eilers , Gunnar Restorff , Efren Ruiz , Adam P. W. Sørensen

Let $G$ be a graph with adjacency matrix $A(G)$ and degree matrix $D(G)$, and let $L_\mu(G):=A(G)-\mu D(G)$. Two graphs $G_1$ and $G_2$ are called \emph{degree-similar} if there exists an invertible matrix $M$ such that $M^{-1} A(G_1) M…

Combinatorics · Mathematics 2025-09-03 Yi-Zheng Fan , Ruo-Jie Xing , Yi-Liu Zhang , Wei Wang

Let $K$ be a field. We characterise the row-finite weighted graphs $(E,w)$ such that the weighted Leavitt path algebra $L_K(E,w)$ is isomorphic to an unweighted Leavitt path algebra. Moreover, we prove that if $L_K(E,w)$ is locally finite,…

Rings and Algebras · Mathematics 2019-07-08 Raimund Preusser

Results of Fowler and Sims show that every k-graph is completely determined by its k-coloured skeleton and collection of commuting squares. Here we give an explicit description of the k-graph associated to a given skeleton and collection of…

Combinatorics · Mathematics 2013-11-01 Robert Hazlewood , Iain Raeburn , Aidan Sims , Samuel B. G. Webster

We classify the rational Cherednik algebras H_c(W) (and their spherical subalgebras) up to isomorphism and Morita equivalence in case when W is the symmetric group and `c' is a generic parameter value.

Quantum Algebra · Mathematics 2007-05-23 Yuri Berest , Pavel Etingof , Victor Ginzburg

Suppose that $R$ is an associative unital ring and that $E=(E^0,E^1,r,s)$ is a directed graph. Utilizing results from graded ring theory we show, that the associated Leavitt path algebra $L_R(E)$ is simple if and only if $R$ is simple,…

Rings and Algebras · Mathematics 2022-12-02 Patrik Lundström , Johan Öinert

Mader [J. Graph Theory 65 (2010) 61-69] conjectured that for every positive integer $k$ and every finite tree $T$ with order $m$, every $k$-connected, finite graph $G$ with $\delta(G)\geq \lfloor\frac{3}{2}k\rfloor+m-1$ contains a subtree…

Combinatorics · Mathematics 2017-10-10 Yingzhi Tian , Hong-Jian Lai , Liqiong Xu , Jixiang Meng

We study the notions of continuous orbit equivalence and eventual one-sided conjugacy of finitely-aligned higher-rank graphs and two-sided conjugacy of row-finite higher-rank graphs with finitely many vertices and no sinks or sources. We…

Operator Algebras · Mathematics 2023-12-29 Toke Meier Carlsen , James Rout

The Graded Classification Conjecture states that the pointed $K_0^{\operatorname{gr}}$-group is a complete invariant of the Leavitt path algebras of finite graphs when these algebras are considered with their natural grading by $\mathbb Z.$…

Rings and Algebras · Mathematics 2025-05-23 Lia Vas

In this paper we give a proof of Enomoto's conjecture for graphs of sufficiently large order. Enomoto's conjecture states that, if $G$ is a graph of order $n$ with minimum degree $\delta(G)\geq \frac{n}{2}+1$, then for any pair of vertices…

Combinatorics · Mathematics 2021-01-14 Weihua He , Hao Li , Qiang Sun

A weighted graph is a graph in which every edge is assigned a non-negative real number. In a weighted graph, the weight of a path is the sum of the weights of its edges, and the weighed degree of a vertex is the sum of the weights of the…

Combinatorics · Mathematics 2011-11-28 Binlong Li , Shenggui Zhang

Let $G$ be a graph such that, whenever two vertices $x$ and $y$ of $G$ are joined by three internally disjoint paths, $x$ and $y$ are adjacent. Jamison and Mulder determined that the set of such graphs coincides with the set of graphs that…

Combinatorics · Mathematics 2023-06-14 Cameron Crenshaw , James Oxley

The last decade has seen the development of path homology and magnitude homology -- two homology theories of directed graphs, each satisfying classic properties such as Kunneth and Mayer-Vietoris theorems. Recent work of Asao has shown that…

Algebraic Topology · Mathematics 2025-03-27 Richard Hepworth , Emily Roff

In this paper we address the classification problem for purely infinite simple Leavitt path algebras of finite graphs over a field $\ell$. Each graph $E$ has associated a Leavitt path $\ell$-algebra $L(E)$. There is an open question which…

Rings and Algebras · Mathematics 2020-01-17 Guillermo Cortiñas , Diego Montero

Intuitively speaking, a bipartite graph is mirror if it can be drawn in the Cartesian plane in such a way that, the vertices of one stable are points in x=0, the vertices of the other stable set are points in x=1, the edges are straight…

Combinatorics · Mathematics 2013-12-13 Susana-Clara López , Francesc-Antoni Muntaner-Batle

Graph classification plays an important role is data mining, and various methods have been developed recently for classifying graphs. In this paper, we propose a novel method for graph classification that is based on homotopy equivalence of…

Discrete Mathematics · Computer Science 2017-07-18 Alexander V. Evako

We describe Morita equivalence of unital locally matrix algebras in terms of their Steinitz parametrization. Two countable dimensional unital locally matrix algebras are Morita equivalent if and only if their Steinitz numbers are rationally…

Rings and Algebras · Mathematics 2020-02-18 Oksana Bezushchak , Bogdana Oliynyk

In this paper we investigate equivariant Morita theory for algebras with momentum maps and compute the equivariant Picard groupoid in terms of the Picard groupoid explicitly. We consider three types of Morita theory: ring-theoretic…

Quantum Algebra · Mathematics 2015-05-18 Stefan Jansen , Nikolai Neumaier , Gregor Schaumann , Stefan Waldmann