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Independently posed by Behzad and Vizing, the Total Coloring Conjecture asserts that the total chromatic number of a simple connected graph $G$ is either $\Delta(G)+1$ or $\Delta(G)+2$, where $\Delta(G)$ is the largest degree of any vertex…

Combinatorics · Mathematics 2026-05-13 I. J. Dejter

An equitable coloring of a graph is a proper coloring where the sizes of any two distinct color classes differ by at most one. The celebrated Chen-Lih-Wu Conjecture (CLWC for short) states that every connected graph $G$ that is neither an…

Combinatorics · Mathematics 2025-09-17 Weichan Liu , Xin Zhang

A graph $G$ is equitably $k$-choosable if, for every $k$-uniform list assignment $L$, $G$ is $L$-colorable and each color appears on at most $\left\lceil |V(G)|/k\right\rceil$ vertices. Equitable list-coloring was introduced by Kostochka,…

Combinatorics · Mathematics 2023-05-24 Kirsten Hogenson , Dan Johnston , Suzanne O'Hara

A collection of graphs is \textit{nearly disjoint} if every pair of them intersects in at most one vertex. We prove that if $G_1, \dots, G_m$ are nearly disjoint graphs of maximum degree at most $D$, then the following holds. For every…

Combinatorics · Mathematics 2023-10-31 Tom Kelly , Daniela Kühn , Deryk Osthus

We continue research into a well-studied family of problems that ask whether the vertices of a graph can be partitioned into sets $A$ and~$B$, where $A$ is an independent set and $B$ induces a graph from some specified graph class ${\cal…

Data Structures and Algorithms · Computer Science 2017-08-01 Marthe Bonamy , Konrad K. Dabrowski , Carl Feghali , Matthew Johnson , Daniel Paulusma

Let ${\cal{F}}=\{F_1,F_2,\ldots\}$ be a sequence of graphs such that $F_n$ is a graph on $n$ vertices with maximum degree at most $\Delta$. We show that there exists an absolute constant $C$ such that the vertices of any 2-edge-colored…

Combinatorics · Mathematics 2014-05-30 Andrey Grinshpun , Gabor N. Sarkozy

The problem of determining the optimal minimum degree condition for a balanced bipartite graph on 2ms vertices to contain m vertex disjoint copies of K_{s,s} was solved by Zhao. Later Hladk\'y and Schacht, and Czygrinow and DeBiasio…

Combinatorics · Mathematics 2013-10-03 Andrzej Czygrinow , Louis DeBiasio

Let $k \in \mathbb{N}$ and let $G$ be a simple graph with maximum degree $\Delta$. A $k$-colouring $\varphi$ of $G$ is an assignment of colours from $\{1,2,\ldots,k\}$ to the vertices of $G$. We call $\varphi$ proper if adjacent vertices…

Combinatorics · Mathematics 2026-04-16 Yuping Gao , Allan Lo , Songling Shan

We study a generalisation of Vizing's theorem, where the goal is to simultaneously colour the edges of graphs $G_1,\dots,G_k$ with few colours. We obtain asymptotically optimal bounds for the required number of colours in terms of the…

Combinatorics · Mathematics 2024-11-07 Simona Boyadzhiyska , Richard Lang , Allan Lo , Michael Molloy

A proper $k$-colouring of a graph $G$ is called $h$-conflict-free if every vertex $v$ has at least $\min\, \{h, {\rm deg}(v)\}$ colours appearing exactly once in its neighbourhood. Let $\chi_{\rm pcf}^h(G)$ denote the minimum $k$ such that…

Combinatorics · Mathematics 2026-02-12 Quentin Chuet , Tianjiao Dai , Qiancheng Ouyang , François Pirot

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

We consider the problem of coloring k-colorable graphs with the fewest possible colors. We present a randomized polynomial time algorithm that colors a 3-colorable graph on $n$ vertices with min O(Delta^{1/3} log^{1/2} Delta log n),…

Data Structures and Algorithms · Computer Science 2007-05-23 David Karger , Rajeev Motwani , Madhu Sudan

In this work we show that, for any fixed d, random d-regular graphs asymptotically almost surely can be coloured with k colours, where k is the smallest integer satisfying d<2(k-1)log(k-1). From previous lower bounds due to Molloy and Reed,…

Combinatorics · Mathematics 2008-12-17 Graeme Kemkes , Xavier Pérez-Giménez , Nicholas Wormald

We study a generalization of the classical Hajnal-Szemer\'edi theorem to vertex-weighted graphs. Given a graph with nonnegative vertex weights, a coloring is called $\alpha$-approximately equitable up to one vertex ($\alpha$-EQ1) if, for…

Data Structures and Algorithms · Computer Science 2026-05-12 Siddharth Barman , Vignesh Viswanathan

In 2003 Kostochka, Pelsmajer, and West introduced a list analogue of equitable coloring called equitable choosability. A $k$-assignment, $L$, for a graph $G$ assigns a list, $L(v)$, of $k$ available colors to each $v \in V(G)$, and an…

Combinatorics · Mathematics 2019-08-06 Jeffrey A. Mudrock , Max Marsh , Tim Wagstrom

Let $c$ be an edge-coloring of the complete $n$-vertex graph $K_n$. The problem of finding properly colored and rainbow Hamilton cycles in $c$ was initiated in 1976 by Bollob\'as and Erd\H os and has been extensively studied since then.…

Combinatorics · Mathematics 2016-10-27 Nina Kamčev , Benny Sudakov , Jan Volec

Let $G$ be a nontrivial connected graph of order $n$ with an edge-coloring $c:E(G)\rightarrow\{1,2,\dots,t\}$,$t\in\mathbb{N}$, where adjacent edges may be colored with the same color. A tree $T$ in $G$ is a \emph{proper tree} if no two…

Combinatorics · Mathematics 2016-12-07 Wenjing Li , Xueliang Li , Jingshu Zhang

We strengthen a result by Laskar and Lyle (Discrete Appl. Math. (2009), 330-338) by proving that it is NP-complete to decide whether a bipartite planar graph can be partitioned into three independent dominating sets. In contrast, we show…

Computational Complexity · Computer Science 2019-05-14 Juho Lauri , Christodoulos Mitillos

A proper coloring of vertices of a graph is equitable if the sizes of any two color classes differ by at most 1. Such colorings have many applications and are interesting by themselves. In this paper, we discuss the state of art and…

Combinatorics · Mathematics 2025-04-22 H. A. Kierstead , Alexandr Kostochka , Zimu Xiang

For planar graphs, we consider the problems of \emph{list edge coloring} and \emph{list total coloring}. Edge coloring is the problem of coloring the edges while ensuring that two edges that are adjacent receive different colors. Total…

Discrete Mathematics · Computer Science 2014-05-15 Marthe Bonamy , Benjamin Lévêque , Alexandre Pinlou