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We consider the problem of list edge coloring for planar graphs. Edge coloring is the problem of coloring the edges while ensuring that two edges that are incident receive different colors. A graph is k-edge-choosable if for any assignment…

Discrete Mathematics · Computer Science 2013-03-19 Marthe Bonamy

A graph is $(d_1, \ldots, d_k)$-colorable if its vertex set can be partitioned into $k$ nonempty subsets so that the subgraph induced by the $i$th part has maximum degree at most $d_i$ for each $i\in\{1, \ldots, k\}$. It is known that for…

Combinatorics · Mathematics 2019-08-09 Ilkyoo Choi , Gexin Yu , Xia Zhang

Let $\chi'_\subset(G)$ be the least number of colours necessary to properly colour the edges of a graph $G$ with minimum degree $\delta\geq 2$ so that the set of colours incident with any vertex is not contained in a set of colours incident…

Combinatorics · Mathematics 2019-09-04 Jakub Kwaśny , Jakub Przybyło

We prove that every graph with circumference at most $k$ is $O(\log k)$-colourable such that every monochromatic component has size at most $O(k)$. The $O(\log k)$ bound on the number of colours is best possible, even in the setting of…

Combinatorics · Mathematics 2018-06-21 Bojan Mohar , Bruce Reed , David R. Wood

A $k$-subcoloring of a graph is a partition of the vertex set into at most $k$ cluster graphs, that is, graphs with no induced $P_3$. 2-subcoloring is known to be NP-complete for comparability graphs and three subclasses of planar graphs,…

Discrete Mathematics · Computer Science 2017-02-07 Pascal Ochem

In this paper we resolve the complexity of the isomorphism problem on all but finitely many of the graph classes characterized by two forbidden induced subgraphs. To this end we develop new techniques applicable for the structural and…

Discrete Mathematics · Computer Science 2014-11-10 Pascal Schweitzer

We prove several results about the complexity of the role colouring problem. A role colouring of a graph $G$ is an assignment of colours to the vertices of $G$ such that two vertices of the same colour have identical sets of colours in…

Data Structures and Algorithms · Computer Science 2014-08-26 Christopher Purcell , M. Puck Rombach

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

For a proper vertex coloring $c$ of a graph $G$, let $\varphi_c(G)$ denote the maximum, over all induced subgraphs $H$ of $G$, the difference between the chromatic number $\chi(H)$ and the number of colors used by $c$ to color $H$. We…

Combinatorics · Mathematics 2014-11-19 N. R. Aravind , Subrahmanyam Kalyanasundaram , R. B. Sandeep , Naveen Sivadasan

We prove that graphs excluding a fixed immersion have bounded nonrepetitive chromatic number. More generally, we prove that if $H$ is a fixed planar graph that has a planar embedding with all the vertices with degree at least 4 on a single…

Combinatorics · Mathematics 2019-07-15 Paul Wollan , David R. Wood

The {\em acyclic chromatic number} of a graph is the least number of colors needed to properly color its vertices so that none of its cycles has only two colors. The {\em acyclic chromatic index} is the analogous graph parameter for edge…

Combinatorics · Mathematics 2024-10-15 Lefteris Kirousis , John Livieratos

An assignment of colours to the vertices of a graph is stable if any two vertices of the same colour have identically coloured neighbourhoods. The goal of colour refinement is to find a stable colouring that uses a minimum number of…

Data Structures and Algorithms · Computer Science 2015-09-29 Christoph Berkholz , Paul Bonsma , Martin Grohe

In this paper we consider a colouring version of the general position problem. The \emph{$\gp $-chromatic number} is the smallest number of colours needed to colour the vertices of the graph such that each colour class has the…

Combinatorics · Mathematics 2025-09-11 Ullas Chandran S. V. , Gabriele Di Stefano , Haritha S. , Elias John Thomas , James Tuite

An edge-coloring of a connected graph $G$ is called a {\em monochromatic connection coloring} (MC-coloring for short) if any two vertices of $G$ are connected by a monochromatic path in $G$. For a connected graph $G$, the {\em monochromatic…

Combinatorics · Mathematics 2020-10-15 Yanhong Gao , Ping Li , Xueliang Li

A lambda colouring (or $L(2,1)-$colouring) of a graph is an assignment of non-negative integers (with minimum assignment $0$) to its vertices such that the adjacent vertices must receive integers at least two apart and vertices at distance…

Combinatorics · Mathematics 2019-01-07 Kaushik Majumder , Ushnish Sarkar

In this paper we study the number of vertex recolorings that an algorithm needs to perform in order to maintain a proper coloring of a graph under insertion and deletion of vertices and edges. We present two algorithms that achieve…

Data Structures and Algorithms · Computer Science 2018-06-26 Luis Barba , Jean Cardinal , Matias Korman , Stefan Langerman , André van Renssen , Marcel Roeloffzen , Sander Verdonschot

A ladder is a $2 \times k$ grid graph. When does a graph class $\mathcal{C}$ exclude some ladder as a minor? We show that this is the case if and only if all graphs $G$ in $\mathcal{C}$ admit a proper vertex coloring with a bounded number…

Combinatorics · Mathematics 2022-10-19 Tony Huynh , Gwenaël Joret , Piotr Micek , Michał T. Seweryn , Paul Wollan

List coloring generalizes graph coloring by requiring the color of a vertex to be selected from a list of colors specific to that vertex. One refinement of list coloring, called choosability with separation, requires that the intersection…

Combinatorics · Mathematics 2015-12-25 Mohit Kumbhat , Kevin Moss , Derrick Stolee

Given an edge-coloring of a simple graph, assign to every vertex $v$ a set $S_v$ comprised of the colors used on the edges incident to $v$. The $k$-intersection chromatic index of a graph is the minimum $t$ such that the edge set can be…

Combinatorics · Mathematics 2015-06-11 M. Santana

This chapter presents an introduction to graph colouring algorithms. The focus is on vertex-colouring algorithms that work for general classes of graphs with worst-case performance guarantees in a sequential model of computation. The…

Data Structures and Algorithms · Computer Science 2015-05-22 Thore Husfeldt