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An edge-weighting of a graph is called vertex-coloring if the weighted degrees yield a proper vertex coloring of the graph. It is conjectured that for every graph without isolated edge, a vertex-coloring edge-weighting with the set {1,2,3}…

Combinatorics · Mathematics 2023-05-04 Ralph Keusch

A colouring of a graph is "nonrepetitive" if for every path of even order, the sequence of colours on the first half of the path is different from the sequence of colours on the second half. We show that planar graphs have nonrepetitive…

Combinatorics · Mathematics 2022-01-24 Vida Dujmović , Louis Esperet , Gwenaël Joret , Bartosz Walczak , David R. Wood

A mixed hypergraph is a triple $H=(V,\mathcal{C},\mathcal{D})$, where $V$ is a set of vertices, $\mathcal{C}$ and $\mathcal{D}$ are sets of hyperedges. A vertex-coloring of $H$ is proper if $C$-edges are not totally multicolored and…

Combinatorics · Mathematics 2014-07-08 Maria Axenovich , Enrica Cherubini , Torsten Ueckerdt

Given a matroid together with a coloring of its ground set, a subset of its elements is called rainbow colored if no two of its elements have the same color. We show that if a binary matroid of rank $r$ is colored with exactly $r$ colors,…

Combinatorics · Mathematics 2021-09-02 Kristóf Bérczi , Tamás Schwarcz

A conflict-free $k$-coloring of a graph $G=(V,E)$ assigns one of $k$ different colors to some of the vertices such that, for every vertex $v$, there is a color that is assigned to exactly one vertex among $v$ and $v$'s neighbors. Such…

Computational Geometry · Computer Science 2017-09-13 Sándor P. Fekete , Phillip Keldenich

This is the second paper in a series of two. The goal of the series is to give a polynomial time algorithm for the $4$-coloring problem and the $4$-precoloring extension problem restricted to the class of graphs with no induced six-vertex…

Combinatorics · Mathematics 2018-02-09 Maria Chudnovsky , Sophie Spirkl , Mingxian Zhong

For graphs of bounded maximum average degree, we consider the problem of 2-distance coloring. This is the problem of coloring the vertices while ensuring that two vertices that are adjacent or have a common neighbor receive different…

Discrete Mathematics · Computer Science 2013-01-31 Marthe Bonamy , Benjamin Lévêque , Alexandre Pinlou

A hole is a chordless cycle with at least four vertices. A hole is odd if it has an odd number of vertices. A dart is a graph which vertices $a, b, c, d, e$ and edges $ab, bc, bd, be, cd, de$. Dart-free graphs have been actively studied in…

Combinatorics · Mathematics 2025-04-30 Chính T. Hoàng

The long-standing Erd\H{o}s-Faber-Lov\'asz conjecture states that every $n$-uniform linear hypergaph with $n$ edges has a proper vertex-coloring using $n$ colors. In this paper we propose an algebraic framework to the problem and formulate…

Combinatorics · Mathematics 2021-05-18 Oliver Janzer , Zoltán Lóránt Nagy

In order to make more complex number-based strings from topological coding for defending against the intelligent attacks equipped with quantum computing and providing effective protection technology for the age of quantum computing, we will…

Cryptography and Security · Computer Science 2024-04-18 Bing Yao , Fei Ma

A {\it mixed hypergraph} ${\cal H}=({\cal V},{\cal C},{\cal D})$ consists of the vertex set ${\cal V}$ and two families of subsets of $2^{{\cal V}}$: the family ${\cal C}$ of co-edges and the family ${\cal D}$ of edges. ${\cal H}$ is said…

Combinatorics · Mathematics 2023-10-11 Meiqiao Zhang , Fengming Dong , Ruixue Zhang

Archdeacon (1987) proved that graphs embeddable on a fixed surface can be $3$-coloured so that each colour class induces a subgraph of bounded maximum degree. Edwards, Kang, Kim, Oum and Seymour (2015) proved that graphs with no…

Combinatorics · Mathematics 2019-07-15 Patrice Ossona de Mendez , Sang-il Oum , David R. Wood

We consider Colouring on graphs that are $H$-subgraph-free for some fixed graph $H$, which are graphs that do not contain $H$ as a subgraph. To classify the complexity of Colouring on $H$-subgraph-free graphs for connected $H$, it remains…

Combinatorics · Mathematics 2026-02-23 Tala Eagling-Vose , Jorik Jooken , Felicia Lucke , Barnaby Martin , Daniël Paulusma

Mixed graphs can be seen as digraphs that have both arcs and edges (or digons, that is, two opposite arcs). In this paper, we consider the case in which such graphs are Cayley graphs of Abelian groups. These groups can be constructed by…

Combinatorics · Mathematics 2020-05-20 C. Dalfó , M. A. Fiol , N. López

We say a graph is $(d, d, \ldots, d, 0, \ldots, 0)$-colorable with $a$ of $d$'s and $b$ of $0$'s if $V(G)$ may be partitioned into $b$ independent sets $O_1,O_2,\ldots,O_b$ and $a$ sets $D_1, D_2,\ldots, D_a$ whose induced graphs have…

Combinatorics · Mathematics 2018-06-20 Michael Kopreski , Gexin Yu

We demonstrate that graph-based models are fully capable of representing higher-order interactions, and have a long history of being used for precisely this purpose. This stands in contrast to a common claim in the recent literature on…

Physics and Society · Physics 2026-02-20 Tiago P. Peixoto , Leto Peel , Thilo Gross , Manlio De Domenico

Given two graphs $H_1$ and $H_2$, a graph is $(H_1,H_2)$-free if it contains no induced subgraph isomorphic to $H_1$ nor $H_2$. A graph $G$ is $k$-vertex-critical if every proper induced subgraph of $G$ has chromatic number less than $k$,…

Combinatorics · Mathematics 2024-03-12 Wen Xia , Jorik Jooken , Jan Goedgebeur , Shenwei Huang

In this paper, two results are obtained on a hypergraph embedding problem. The proof technique is itself of interest, being the first time amalgamations have been used to address the embedding of hypergraphs. The first result finds…

Combinatorics · Mathematics 2017-10-18 Amin Bahmanian , Chris Rodger

The \emph{Square Colouring} of a graph $G$ refers to colouring of vertices of a graph such that any two distinct vertices which are at distance at most two receive different colours. In this paper, we initiate the study of a related…

Computational Complexity · Computer Science 2023-03-14 V P Abidha , Pradeesha Ashok , Avi Tomar , Dolly Yadav

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