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Related papers: Breaking graph symmetries by edge colourings

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A proper edge $k$-colouring of a graph $G=(V,E)$ is an assignment $c:E\to \{1,2,\ldots,k\}$ of colours to the edges of the graph such that no two adjacent edges are associated with the same colour. A neighbour sum distinguishing edge…

Combinatorics · Mathematics 2018-03-07 Hervé Hocquard , Jakub Przybyło

Let G be a simple, finite, connected, and undirected graph. The middle graph M(G) of G is obtained from the subdivision graph S(G) after joining pairs of subdivided vertices that lie on adjacent edges of G and the central graph C(G) of G is…

Combinatorics · Mathematics 2026-04-09 Amitayu Banerjee , Alexa Gopaulsingh , Zalán Molnár

A proper edge colouring of a graph is adjacent vertex distinguishing if no two adjacent vertices see the same set of colours. Using a clever application of the Local Lemma, Hatami (2005) proved that every graph with maximum degree $\Delta$…

Combinatorics · Mathematics 2020-11-04 Gwenaël Joret , William Lochet

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 present results on partitioning the vertices of $2$-edge-colored graphs into monochromatic paths and cycles. We prove asymptotically the two-color case of a conjecture of S\'ark\"ozy: the vertex set of every $2$-edge-colored graph can be…

Combinatorics · Mathematics 2015-09-21 Jozsef Balogh , Janos Barat , Daniel Gerbner , Andras Gyarfas , GAbor N. Sarkozy

An \emph{interval $t$-coloring} of a multigraph $G$ is a proper edge coloring with colors $1,\dots,t$ such that the colors on the edges incident to every vertex of $G$ are colored by consecutive colors. A \emph{cyclic interval $t$-coloring}…

Combinatorics · Mathematics 2016-11-22 Carl Johan Casselgren , Hrant H. Khachatrian , Petros A. Petrosyan

For a graph $G$ and an integer $k\geq 2$, a $\chi'_{k}$-coloring of $G$ is an edge coloring of $G$ such that the subgraph induced by the edges of each color has all degrees congruent to $1 ~ (\mod k)$, and $\chi'_{k}(G)$ is the minimum…

Combinatorics · Mathematics 2024-11-13 Oothan Nweit , Daqing Yang

A cycle is $2$-colored if its edges are properly colored by two distinct colors. A $(d,s)$-edge colorable graph $G$ is a $d$-regular graph that admits a proper $d$-edge coloring in which every edge of $G$ is in at least $s-1$ $2$-colored…

Combinatorics · Mathematics 2019-05-28 Lan Anh Pham

A graph $G$ is said to be perfectly divisible if for every induced subgraph $H$ of $G$ with at least one edge, the vertex set $V(H)$ can be partitioned into two sets $A, B$ such that $H[A]$ is perfect and $\omega(B) < \omega(H)$. It is easy…

Combinatorics · Mathematics 2026-05-12 Hongzhang Chen , Kaiyang Lan , Wenlong Zhong

A graph automorphism is a bijective mapping of the vertices that preserves adjacent vertices. A vertex determining set of a graph is a set of vertices such that the only automorphism that fixes those vertices is the identity. The size of a…

Combinatorics · Mathematics 2024-06-12 Sean McAvoy , Sally Cockburn

A strong edge coloring of a graph is a proper edge coloring in which every color class is an induced matching. The strong chromatic index $\chi_s'(G)$ of a graph $G$ is the minimum number of colors in a strong edge coloring of $G$. Let…

Combinatorics · Mathematics 2018-02-20 Tao Wang , Xiaodan Zhao

Given a graph $G$ and an integer $k\geq 2$, let $\chi'_k(G)$ denote the minimum number of colours required to colour the edges of $G$ such that, in each colour class, the subgraph induced by the edges of that colour has all non-zero degrees…

Let $G$ be a graph with maximum degree $\Delta(G)$ and maximum multiplicity $\mu(G)$. Vizing and Gupta, independently, proved in the 1960s that the chromatic index of $G$ is at most $\Delta(G)+\mu(G)$. The distance between two edges $e$ and…

Combinatorics · Mathematics 2022-04-05 Yan Cao , Guantao Chen , Guangming Jing , Xuli Qi , Songling Shan

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

The \textit{Distinguishing Chromatic Number} of a graph $G$, denoted $\chi_D(G)$, was first defined in \cite{collins} as the minimum number of colors needed to properly color $G$ such that no non-trivial automorphism $\phi$ of the graph $G$…

Combinatorics · Mathematics 2015-05-14 Niranjan Balachandran , Sajith Padinhatteeri

A strong edge colouring of a graph is an assignment of colours to the edges of the graph such that for every colour, the set of edges that are given that colour form an induced matching in the graph. The strong chromatic index of a graph…

Combinatorics · Mathematics 2013-08-20 Manu Basavaraju , Mathew C. Francis

We supply an upper bound on the distinguishing chromatic number of certain infinite graphs satisfying an adjacency property. Distinguishing proper $n$-colourings are generalized to the new notion of distinguishing homomorphisms. We prove…

Combinatorics · Mathematics 2013-09-03 Anthony Bonato , Dejan Delic

Let $k \ge 1$ be an integer and let $G$ be a nonempty simple graph. An \emph{edge-$k$-coloring} $\varphi$ of $G$ is an assignment of colors from $\{1,\ldots,k\}$ to the edges of $G$ such that no two adjacent edges receive the same color.…

Combinatorics · Mathematics 2025-12-12 Yuping Gao , Songling Shan , Guanghui Wang , Yiming Zhou

Let $\chi'_k(G)$ denote the minimum number of colors needed to color the edges of a graph $G$ in a way that the subgraph spanned by the edges of each color has all degrees congruent to $1 \pmod k$. Scott [{\em Discrete Math. 175}, 1-3…

Combinatorics · Mathematics 2020-07-17 Fábio Botler , Lucas Colucci , Yoshiharu Kohayakawa

A conjecture due to the fourth author states that every $d$-regular planar multigraph can be $d$-edge-coloured, provided that for every odd set $X$ of vertices, there are at least $d$ edges between $X$ and its complement. For $d = 3$ this…

Discrete Mathematics · Computer Science 2012-10-30 Maria Chudnovsky , Katherine Edwards , Ken-ichi Kawarabayashi , Paul Seymour