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We investigate the class of the edge-shelling convex geometries of trees. The edge-shelling convex geometry of a tree is the convex geometry consisting of the sets of edges of the subtrees. For the edge-shelling convex geometry of a tree,…

Combinatorics · Mathematics 2009-08-25 Kenji Kashiwabara , Masataka Nakamura

In this article, we explicitly derive the limiting degree distribution of the shortest path tree from a single source on various random network models with edge weights. We determine the asymptotics of the degree distribution for large…

Probability · Mathematics 2016-08-11 Shankar Bhamidi , Jesse Goodman , Remco van der Hofstad , Júlia Komjáthy

In graph theory, a tree is one of the more popular families of graphs with a wide range of applications in computer science as well as many other related fields. While there are several distance measures over the set of all trees, we…

Information Theory · Computer Science 2021-02-04 Lev Yohananov , Eitan yaakobi

A weighted coloured-edge graph is a graph for which each edge is assigned both a positive weight and a discrete colour, and can be used to model transportation and computer networks in which there are multiple transportation modes. In such…

Combinatorics · Mathematics 2011-12-15 Andrew Ensor , Felipe Lillo

Two graph parameters are said to be coarsely equivalent if they are within constant factors from each other for every graph $G$. Recently, several graph parameters were shown to be coarsely equivalent to tree-length. Recall that the length…

Combinatorics · Mathematics 2025-02-04 Feodor F. Dragan

Let $G$ be a simple graph. A dissociation set of $G$ is defined as a set of vertices that induces a subgraph in which every vertex has a degree of at most 1. A dissociation set is maximal if it is not contained as a proper subset in any…

Combinatorics · Mathematics 2024-10-29 Ziyuan Wang , Lei Zhang , Jianhua Tu , Liming Xiong

Given an edge-coloring of a graph, the palette of a vertex is defined as the set of colors of the edges which are incident with it. We define the palette index of a graph as the minimum number of distinct palettes, taken over all…

Combinatorics · Mathematics 2021-07-09 Davide Mattiolo , Giuseppe Mazzuoccolo , Gloria Tabarelli

A vertex of degree one in a tree is called an end vertex and a vertex of degree at least three is called a branch vertex. For a graph $G$, let $\sigma_2$ be the minimum degree sum of two nonadjacent vertices in $G$. We consider tree…

Combinatorics · Mathematics 2015-05-19 Zhora Nikoghosyan

Let $k$, $d$ be a positive integer, $G$ be a connected graph of order $n$, $T$ be a tree. The leaf distance of a tree is defined as the minimum distance between any two leaves. For $v\in V(T)$, the leaf degree of $v$ in $T$ is the number of…

Combinatorics · Mathematics 2025-01-15 Jifu Lin , Lihua You

A consistent path system in a graph $G$ is an collection of paths, with exactly one path between any two vertices in $G$. A path system is said to be consistent if it is intersection-closed. We say that $G$ is strictly metrizable if every…

Combinatorics · Mathematics 2025-01-24 Maria Chudnovsky , Daniel Cizma , Nati Linial

We consider the worst-case query complexity of some variants of certain \cl{PPAD}-complete search problems. Suppose we are given a graph $G$ and a vertex $s \in V(G)$. We denote the directed graph obtained from $G$ by directing all edges in…

Combinatorics · Mathematics 2017-07-28 Dániel Gerbner , Balázs Keszegh , Dömötör Pálvölgyi , Günter Rote , Gábor Wiener

We are interested in embedding trees T with maximum degree at most four in a rectangular grid, such that the vertices of T correspond to grid points, while edges of T correspond to non-intersecting straight segments of the grid lines. Such…

Combinatorics · Mathematics 2021-09-08 V. T. F. Luca , F. S. Oliveira , J. L. Szwarcfiter

For a class $\mathcal C$ of graphs, we define $\mathcal C$-edge-brittleness of a graph $G$ as the minimum $\ell$ such that the vertex set of $G$ can be partitioned into sets inducing a subgraph in $\mathcal C$ and there are $\ell$ edges…

Combinatorics · Mathematics 2020-11-05 Ringi Kim , Sergey Norin , Sang-il Oum

This paper addresses the following questions for a given tree $T$ and integer $d\geq2$: (1) What is the minimum number of degree-$d$ subtrees that partition $E(T)$? (2) What is the minimum number of degree-$d$ subtrees that cover $E(T)$? We…

Combinatorics · Mathematics 2010-08-20 David R. Wood

A \emph{tree-partition} of a graph $G$ is a proper partition of its vertex set into `bags', such that identifying the vertices in each bag produces a forest. The \emph{tree-partition-width} of $G$ is the minimum number of vertices in a bag…

Combinatorics · Mathematics 2009-04-02 David R. Wood

A $k$-nearly independent vertex subset of a graph $G$ is a set of vertices that induces a subgraph containing exactly $k$ edges. For $k = 0$, this coincides with the classical notion of independent subsets. This paper investigates the…

Combinatorics · Mathematics 2025-10-29 Audace A. V. Dossou-Olory , Eric O. Andriantiana

A graph $G=(V,E)$ with a vertex set $V$ and an edge set $E$ is called a pairwise compatibility graph (PCG, for short) if there are a tree $T$ whose leaf set is $V$, a non-negative edge weight $w$ in $T$, and two non-negative reals…

Data Structures and Algorithms · Computer Science 2020-07-23 Mingyu Xiao , Hiroshi Nagamochi

In an EPG-representation of a graph $G$ each vertex is represented by a path in the rectangular grid, and $(v,w)$ is an edge in $G$ if and only if the paths representing $v$ an $w$ share a grid-edge. Requiring paths representing edges to be…

Computational Geometry · Computer Science 2017-09-05 Therese Biedl , Martin Derka , Vida Dujmovic , Pat Morin

Two graph parameters are said to be coarsely equivalent if they are within constant factors from each other for every graph $G$. Recently, several graph parameters were shown to be coarsely equivalent to tree-length. Recall that the length…

Combinatorics · Mathematics 2025-04-02 Feodor F. Dragan , Ekkehard Köhler

The number of spanning trees in a graph $G$ is the total number of distinct spanning subgraphs of $G$ that are trees. In this paper we characterize the unique graph with a prescribed vertex (resp. edge) connectivity, minimum degree and…

Combinatorics · Mathematics 2025-12-16 Shaohan Xu , Kexiang Xu , Ivan Damnjanović