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We study a restricted form of list colouring, for which every pair of lists that correspond to adjacent vertices may not share more than one colour. The optimal list size such that a proper list colouring is always possible given this…

Combinatorics · Mathematics 2019-08-15 Louis Esperet , Ross J. Kang , Stéphan Thomassé

In 1965, Vizing [Diskret. Analiz, 1965] showed that every planar graph of maximum degree $\Delta\ge 8$ can be edge-colored using $\Delta$ colors. The direct implementation of the Vizing's proof gives an algorithm that finds the coloring in…

Data Structures and Algorithms · Computer Science 2026-05-06 Patryk Jędrzejczak , Łukasz Kowalik

For a graph $G$, we show that if $mad(G)<m$, then $\chi'_\ell(G)\leq \Delta+1$ where $m$ depends upon $\Delta$ and $\chi'_\ell(G)$ is the list-chromatic index of $G$. When $\Delta\leq 20$ the value of $m$ is close to $\frac{1}{2}\Delta$,…

Combinatorics · Mathematics 2023-05-05 Joshua Harrelson

We show that every Borel graph $G$ of subexponential growth has a Borel proper edge-coloring with $\Delta(G) + 1$ colors. We deduce this from a stronger result, namely that an $n$-vertex (finite) graph $G$ of subexponential growth can be…

Combinatorics · Mathematics 2024-08-22 Anton Bernshteyn , Abhishek Dhawan

An adjacent vertex distinguishing edge colouring of a graph $G$ without isolated edges is its proper edge colouring such that no pair of adjacent vertices meets the same set of colours in $G$. We show that such colouring can be chosen from…

Combinatorics · Mathematics 2019-01-08 Jakub Kwaśny , Jakub Przybyło

A locally irregular multigraph is a multigraph whose adjacent vertices have distinct degrees. The locally irregular edge coloring is an edge coloring of a multigraph $G$ such that every color induces a locally irregular submultigraph of…

Combinatorics · Mathematics 2022-08-19 Igor Grzelec , Mariusz Woźniak

A {\em strong $k$-edge-coloring} of a graph $G$ is a mapping from $E(G)$ to $\{1,2,\ldots,k\}$ such that every two adjacent edges or two edges adjacent to the same edge receive distinct colors. The {\em strong chromatic index} $\chi_s'(G)$…

Combinatorics · Mathematics 2018-01-24 Ilkyoo Choi , Jaehoon Kim , Alexandr V. Kostochka , André Raspaud

For a graph $G$ with a list assignment $L$ and two $L$-colorings $\alpha$ and $\beta$, an $L$-recoloring sequence from $\alpha$ to $\beta$ is a sequence of proper $L$-colorings where consecutive colorings differ at exactly one vertex. We…

Combinatorics · Mathematics 2025-10-21 Chenran Pan , Weifan Wang , Runrun Liu

We develop an improved bound for the chromatic number of graphs of maximum degree $\Delta$ under the assumption that the number of edges spanning any neighbourhood is at most $(1-\sigma)\binom{\Delta}{2}$ for some fixed $0<\sigma<1$. The…

Combinatorics · Mathematics 2022-09-13 Eoin Hurley , Rémi de Joannis de Verclos , Ross J. Kang

A total coloring of a graph $G$ is a coloring of its vertices and edges such that no adjacent vertices, edges, and no incident vertices and edges obtain the same color. An interval total $t$-coloring of a graph $G$ is a total coloring of…

Combinatorics · Mathematics 2014-08-12 Petros A. Petrosyan , Nerses A. Khachatryan

In this paper, we consider algorithms for edge-coloring multigraphs $G$ of bounded maximum degree, i.e., $\Delta(G) = O(1)$. Shannon's theorem states that any multigraph of maximum degree $\Delta$ can be properly edge-colored with…

Data Structures and Algorithms · Computer Science 2023-10-31 Abhishek Dhawan

A vertex coloring of a graph G is called a 2-distance coloring if any two vertices at a distance at most 2 from each other receive different colors. Suppose that G is a planar graph with a maximum degree at most 5. We prove that G admits a…

Combinatorics · Mathematics 2025-08-21 Zakir Deniz

A star $k$-edge coloring is a proper edge coloring such that there are no bichromatic paths or cycles of length four. The smallest integer $k$ such that $G$ admits a star $k$-edge coloring is the star chromatic index of $G$. Deng \etal…

Combinatorics · Mathematics 2021-06-22 Zhengke Miao , Yimin Song , Tao Wang , Xiaowei Yu

Hajnal and Szemer\'{e}di proved that if $G$ is a finite graph with maximum degree $\Delta$, then for every integer $k \geqslant \Delta+1$, $G$ has a proper coloring with $k$ colors in which every two color classes differ in size at most by…

Combinatorics · Mathematics 2021-10-04 Anton Bernshteyn , Clinton T. Conley

It is known (Bollob\'{a}s (1978); Kostochka and Mazurova (1977)) that there exist graphs of maximum degree $\Delta$ and of arbitrarily large girth whose chromatic number is at least $c \Delta / \log \Delta$. We show an analogous result for…

Combinatorics · Mathematics 2011-10-25 Ararat Harutyunyan , Bojan Mohar

The star chromatic index of a multigraph $G$, denoted $\chi'_{s}(G)$, is the minimum number of colors needed to properly color the edges of $G$ such that no path or cycle of length four is bi-colored. A multigraph $G$ is star…

Combinatorics · Mathematics 2017-11-23 Hui Lei , Yongtang Shi , Zi-Xia Song

Let $k$ and $r$ be two integers with $k \ge 2$ and $k\ge r \ge 1$. In this paper we show that (1) if a strongly connected digraph $D$ contains no directed cycle of length $1$ modulo $k$, then $D$ is $k$-colorable; and (2) if a digraph $D$…

Combinatorics · Mathematics 2014-04-01 Zhibin Chen , Jie Ma , Wenan Zang

A coloring of the edges of a graph $G$ is strong if each color class is an induced matching of $G$. The strong chromatic index of $G$, denoted by $\chi_{s}^{\prime}(G)$, is the least number of colors in a strong edge coloring of $G$. In…

Combinatorics · Mathematics 2016-08-11 Michał Dębski , Jarosław Grytczuk , Małgorzata Śleszyńska-Nowak

For graphs $G$ and $H$, a homomorphism from $G$ to $H$, or $H$-coloring of $G$, is a map from the vertices of $G$ to the vertices of $H$ that preserves adjacency. When $H$ is composed of an edge with one looped endvertex, an $H$-coloring of…

Combinatorics · Mathematics 2016-10-21 John Engbers

We obtain the following new coloring results: * A 3-colorable graph on $n$ vertices with maximum degree~$\Delta$ can be colored, in polynomial time, using $O((\Delta \log\Delta)^{1/3} \cdot\log{n})$ colors. This slightly improves an…

Data Structures and Algorithms · Computer Science 2016-08-31 Eran Halperin , Ram Nathaniel , Uri Zwick