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We give sufficient conditions under which a random graph with a specified degree sequence is symmetric or asymmetric. In the case of bounded degree sequences, our characterisation captures the phase transition of the symmetry of the random…

Combinatorics · Mathematics 2020-04-07 Lochlan Brick , Pu Gao , Angus Southwell

A strong odd coloring of a simple graph $G$ is a proper coloring of the vertices of $G$ such that for every vertex $v$ and every color $c$, either $c$ is used an odd number of times in the open neighborhood $N_G(v)$ or no neighbor of $v$ is…

Combinatorics · Mathematics 2024-10-04 Yair Caro , Mirko Petruševski , Riste Škrekovski , Zsolt Tuza

Let $G$ be a connected undirected graph.~A vertex coloring $f$ of $G$ is an $N_i$-vertex coloring if for each vertex $x$ in $G$, the number of different colors assigned to $N_G(x)$ is at most $i$.~The $N_i$-chromatic number of $G$, denoted…

Combinatorics · Mathematics 2022-08-22 Yangfan Yu , Yuefang Sun

A labelling of a graph is an assignment of labels to its vertex or edge sets (or both), subject to certain conditions, a well established concept. A labelling of a graph G of order n is termed a numbering when the set of integers {1,...,n}…

Combinatorics · Mathematics 2023-06-06 Les Foulds , Humberto J. Longo

A coloring of edges of a graph $G$ is injective if for any two distinct edges $e_1$ and $e_2$, the colors of $e_1$ and $e_2$ are distinct if they are at distance $1$ in $G$ or in a common triangle. Naturally, the injective chromatic index…

Combinatorics · Mathematics 2021-04-26 Alexandr Kostochka , André Raspaud , Jingwei Xu

We prove that for every $d\in \mathbb{N}$ and a graph class of bounded expansion $\mathscr{C}$, there exists some $c\in \mathbb{N}$ so that every graph from $\mathscr{C}$ admits a proper coloring with at most $c$ colors satisfying the…

Combinatorics · Mathematics 2025-05-22 Michał Pilipczuk

An outerstring graph is an intersection graph of curves that lie in a common half-plane and have one endpoint on the boundary of that half-plane. We prove that the class of outerstring graphs is $\chi$-bounded, which means that their…

Combinatorics · Mathematics 2018-12-04 Alexandre Rok , Bartosz Walczak

Given a graph $G=(V,E)$ on $n$ vertices and an assignment of colours to its edges, a set of edges $S \subseteq E$ is said to be rainbow if edges from $S$ have pairwise different colours assigned to them. In this paper, we investigate…

Combinatorics · Mathematics 2023-11-02 Deepak Bal , Alan Frieze , Pawel Pralat

In this paper, we consider a weighted generalization of the chromatic number of a Binomial random graph~\(G.\) We equip each edge with a random weight and then colour the vertices in such a way that the absolute colour difference between…

Combinatorics · Mathematics 2023-11-21 Ghurumuruhan Ganesan

The $d$-independence number of a graph $G$ is the largest possible size of an independent set $I$ in $G$ where each vertex of $I$ has degree at least $d$ in $G$. Upper bounds for the $d$-independence number in planar graphs are well-known…

Combinatorics · Mathematics 2024-11-06 Therese Biedl , Prosenjit Bose , Babak Miraftab

A graph $G$ is \emph{chordless} if no cycle in $G$ has a chord. In the present work we investigate the chromatic index and total chromatic number of chordless graphs. We describe a known decomposition result for chordless graphs and use it…

Discrete Mathematics · Computer Science 2013-09-10 Raphael C. S. Machado , Celina M. H. de Figueiredo , Nicolas Trotignon

We study some properties of graphs (or, rather, graph sequences) defined by demanding that the number of subgraphs of a given type, with vertices in subsets of given sizes, approximatively equals the number expected in a random graph. It…

Combinatorics · Mathematics 2014-05-28 Svante Janson , Vera T. Sós

The maximum edge colouring problem considers the maximum colour assignment to edges of a graph under the condition that every vertex has at most a fixed number of distinct coloured edges incident on it. If that fixed number is $q$ we call…

Discrete Mathematics · Computer Science 2023-07-06 Zdeněk Dvořák , Abhiruk Lahiri

The burning number of a graph was recently introduced by Bonato et al. Although they mention that the burning number generalises naturally to directed graphs, no further research on this has been done. Here, we introduce graph burning for…

Combinatorics · Mathematics 2020-01-13 Remie Janssen

We introduce the triple crossing number, a variation of crossing number, of a graph, which is the minimal number of crossing points in all drawings with only triple crossings of the graph. It is defined to be zero for a planar graph, and to…

Combinatorics · Mathematics 2012-01-16 Hiroyuki Tanaka , Masakazu Teragaito

A drawing of a graph is {\em pseudolinear} if there is a pseudoline arrangement such that each pseudoline contains exactly one edge of the drawing. The {\em pseudolinear crossing number} of a graph $G$ is the minimum number of pairwise…

Combinatorics · Mathematics 2019-04-29 Cesar Hernandez-Velez , Jesus Leanos , Gelasio Salazar

For a connected graph, we define the proper-walk connection number as the minimum number of colors needed to color the edges of a graph so that there is a walk between every pair of vertices without two consecutive edges having the same…

Combinatorics · Mathematics 2017-04-25 Robert Melville , Wayne Goddard

Let $\mathcal{C}_4(n)$ be the family of all connected $4$-chromatic graphs of order $n$. Given an integer $x\geq 4$, we consider the problem of finding the maximum number of $x$-colorings of a graph in $\mathcal{C}_4(n)$. It was conjectured…

Combinatorics · Mathematics 2021-06-02 Aysel Erey

A coloring of edges of a finite directed graph turns the graph into finite-state automaton. The synchronizing word of a deterministic automaton is a word in the alphabet of colors (considered as letters) of its edges that maps the automaton…

Discrete Mathematics · Computer Science 2010-11-24 A. N. Trahtman

Consider the complete n-vertex graph whose edge-lengths are independent exponentially distributed random variables. Simultaneously for each pair of vertices, put a constant flow between them along the shortest path. Each edge gets some…

Probability · Mathematics 2007-08-06 David J. Aldous , Shankar Bhamidi