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Let $G$ be an edge-coloured graph. The minimum colour degree $\delta^c(G)$ of $G$ is the largest integer $k$ such that, for every vertex $v$, there are at least $k$ distinct colours on edges incident to $v$. We say that $G$ is properly…

Combinatorics · Mathematics 2018-08-14 Allan Lo

We give a probabilistic analysis of a Moser-type algorithm for the Lov\'{a}sz Local Lemma (LLL), adjusted to search for acyclic edge colorings of a graph. We thus improve the best known upper bound to acyclic chromatic index, also obtained…

Discrete Mathematics · Computer Science 2018-01-09 Ioannis Giotis , Lefteris Kirousis , Kostas I. Psaromiligkos , Dimitrios M. Thilikos

An edge-coloring of a graph G is acyclic if it is a proper edge-coloring of G and every cycle contains at least three colors. We prove that every graph with maximum degree Delta has an acyclic edge-coloring with at most 4 Delta - 4 colors,…

Combinatorics · Mathematics 2013-03-20 Louis Esperet , Aline Parreau

A proper edge coloring of a graph $G$ with colors $1,2,\dots,t$ is called a cyclic interval $t$-coloring if for each vertex $v$ of $G$ the edges incident to $v$ are colored by consecutive colors, under the condition that color $1$ is…

Combinatorics · Mathematics 2017-11-15 Armen S. Asratian , Carl Johan Casselgren , Petros A. Petrosyan

An acyclic edge coloring of a graph $G$ is a proper edge coloring such that no bichromatic cycles are produced. The acyclic chromatic index $a'(G)$ of $G$ is the smallest integer $k$ such that $G$ has an acyclic edge coloring using $k$…

Combinatorics · Mathematics 2012-06-01 Weifan Wang , Qiaojun Shu , Yiqiao Wang

An $acyclic$ edge coloring of a graph is a proper edge coloring such that there are no bichromatic cycle s. The \emph{acyclic chromatic index} of a graph is the minimum number k such that there is an acyclic e dge coloring using k colors…

Combinatorics · Mathematics 2008-10-20 Manu Basavaraju , L. Sunil Chandran

Graph colorings is a fundamental topic in graph theory that require an assignment of labels (or colors) to vertices or edges subject to various constraints. We focus on the harmonious coloring of a graph, which is a proper vertex coloring…

Discrete Mathematics · Computer Science 2021-06-02 Ruxandra Marinescu-Ghemeci , Camelia Obreja , Alexandru Popa

An edge coloring of a graph $G$ is to color all the edges in the graph such that adjacent edges receive different colors. It is acyclic if each cycle in the graph receives at least three colors. Fiam{\v{c}}ik (1978) and Alon, Sudakov and…

Discrete Mathematics · Computer Science 2023-06-29 Qiaojun Shu , Guohui Lin

In this note we obtain a new bound for the acyclic edge chromatic number $a'(G)$ of a graph $G$ with maximum degree $D$ proving that $a'(G)\leq 3.569(D-1)$. To get this result we revisit and slightly modify the method described in [Giotis,…

Combinatorics · Mathematics 2019-12-11 Paula M. S. Fialho , Bernardo N. B. de Lima , Aldo Procacci

We consider two graph colouring problems in which edges at distance at most $t$ are given distinct colours, for some fixed positive integer $t$. We obtain two upper bounds for the distance-$t$ chromatic index, the least number of colours…

Combinatorics · Mathematics 2015-10-29 Tomáš Kaiser , Ross J. Kang

An edge colouring of a graph $G$ is called acyclic if it is proper and every cycle contains at least three colours. We show that for every $\varepsilon>0$, there exists a $g=g(\varepsilon)$ such that if $G$ has girth at least $g$ then $G$…

Combinatorics · Mathematics 2020-04-21 Xing Shi Cai , Guillem Perarnau , Bruce Reed , Adam Bene Watts

We consider vertex coloring of an acyclic digraph $\Gdag$ in such a way that two vertices which have a common ancestor in $\Gdag$ receive distinct colors. Such colorings arise in a natural way when bounding space for various genetic data…

Combinatorics · Mathematics 2007-06-12 Geir Agnarsson , Agust Egilsson , Magnus Mar Halldorsson

A strong edge-coloring of a graph $G$ is a coloring of the edges such that every color class induces a matching in $G$. The strong chromatic index of a graph is the minimum number of colors needed in a strong edge-coloring of the graph. In…

Combinatorics · Mathematics 2018-06-20 Mingfang Huang , Michael Santana , Gexin Yu

The conflict-free chromatic index of a graph $G$ is the minimum number of colours in an edge colouring of $G$ such that the neighbourhood of every edge contains a colour appearing exactly once. Its vertex analogue is the conflict-free…

Combinatorics · Mathematics 2026-04-27 Mateusz Kamyczura , Jakub Przybyło

The problem of finding the minimum number of colors to color a graph properly without containing any bicolored copy of a fixed family of subgraphs has been widely studied. Most well-known examples are star coloring and acyclic coloring of…

Combinatorics · Mathematics 2023-11-09 Alaittin Kırtışoğlu , Lale Özkahya

In many practical applications the underlying graph must be as equitable colored as possible. A coloring is called equitable if the number of vertices colored with each color differs by at most one, and the least number of colors for which…

Combinatorics · Mathematics 2021-07-01 Emanuel Florentin Olariu , Cristian Frasinaru

A proper edge coloring of a graph $G$ with colors $1,2,\dots,t$ is called a \emph{cyclic interval $t$-coloring} if for each vertex $v$ of $G$ the edges incident to $v$ are colored by consecutive colors, under the condition that color $1$ is…

Combinatorics · Mathematics 2017-03-30 Armen S. Asratian , Carl Johan Casselgren , Petros A. Petrosyan

The star chromatic index $\chi_s'(G)$ of a graph $G$ is the minimum number of colors needed to properly color the edges of the graph so that no path or cycle of length four is bi-colored. We obtain a near-linear upper bound in terms of the…

Combinatorics · Mathematics 2015-03-17 Zdeněk Dvořák , Bojan Mohar , Robert Šámal

A well-studied concept is that of the total chromatic number. A proper total colouring of a graph is a colouring of both vertices and edges so that every pair of adjacent vertices receive different colours, every pair of adjacent edges…

Combinatorics · Mathematics 2010-09-14 Tom Coker , Karen Johannson

A strong edge-coloring of a graph $G$ is an edge-coloring such that no two edges of distance at most two receive the same color. The strong chromatic index $\chi'_s(G)$ is the minimum number of colors in a strong edge-coloring of $G$. P.…

Combinatorics · Mathematics 2015-10-06 Chuanyun Zang