Results 11 to 20 of about 4,584 (263)
On graphs double-critical with respect to the colouring number [PDF]
Discrete Mathematics & Theoretical Computer Science, 2015 The colouring number col($G$) of a graph $G$ is the smallest integer $k$ for which there is an ordering of the vertices of $G$ such that when removing the vertices of $G$ in the specified order no vertex of degree more than $k-1$ in the remaining graph ...
Matthias Kriesell, Anders Pedersen
doaj +1 more source
Acyclic, Star and Oriented Colourings of Graph Subdivisions [PDF]
Discrete Mathematics & Theoretical Computer Science, 2005 Let G be a graph with chromatic number χ (G). A vertex colouring of G is \emphacyclic if each bichromatic subgraph is a forest. A \emphstar colouring of G is an acyclic colouring in which each bichromatic subgraph is a star forest. Let χ _a(G) and χ _s(G)
David R. Wood
doaj +3 more sources
Measurable versions of Vizing's theorem [PDF]
, 2020 We establish two versions of Vizing's theorem for Borel multi-graphs whose vertex degrees and edge multiplicities are uniformly bounded by respectively $\Delta$ and $\pi$.
Grebík, Jan, Pikhurko, Oleg
core +2 more sources
On Small Balanceable, Strongly-Balanceable and Omnitonal Graphs
Discussiones Mathematicae Graph Theory, 2022 In Ramsey Theory for graphs we are given a graph G and we are required to find the least n0 such that, for any n ≥ n0, any red/blue colouring of the edges of Kn gives a subgraph G all of whose edges are blue or all are red.
Caro Yair, Lauri Josef, Zarb Christina
doaj +1 more source
Strong edge-colouring of sparse planar graphs [PDF]
, 2014 A strong edge-colouring of a graph is a proper edge-colouring where each colour class induces a matching. It is known that every planar graph with maximum degree $\Delta$ has a strong edge-colouring with at most $4\Delta+4$ colours. We show that $3\Delta+
Bensmail, Julien +3 more
core +5 more sources
A note on the size Ramsey numbers for matchings versus cycles [PDF]
Mathematica Bohemica, 2021 For graphs $G$, $F_1$, $F_2$, we write $G \rightarrow(F_1, F_2)$ if for every red-blue colouring of the edge set of $G$ we have a red copy of $F_1$ or a blue copy of $F_2$ in $G$.
Edy Tri Baskoro, Tomáš Vetrík
doaj +1 more source
Tutte's Edge-Colouring Conjecture
Journal of Combinatorial Theory, Series B, 1997 In 1966 Tutte conjectured that every 2-connected cubic graph not containing the Petersen graph as a minor is 3-edge-colourable. The conjecture is still open, but it is shown in this paper that it is true in general, provided that it is true for two special kinds of cubic graphs that are almost planar.
Robertson, Neil +2 more
openaire +2 more sources
Line game-perfect graphs [PDF]
Discrete Mathematics & Theoretical Computer ScienceThe $[X,Y]$-edge colouring game is played with a set of $k$ colours on a graph $G$ with initially uncoloured edges by two players, Alice (A) and Bob (B). The players move alternately. Player $X\in\{A,B\}$ has the first move. $Y\in\{A,B,-\}$.
Stephan Dominique Andres, Wai Lam Fong
doaj +1 more source
GRACEFUL CHROMATIC NUMBER OF SOME CARTESIAN PRODUCT GRAPHS
Ural Mathematical Journal, 2023 A graph \(G(V,E)\) is a system consisting of a finite non empty set of vertices \(V(G)\) and a set of edges \(E(G)\). A (proper) vertex colouring of \(G\) is a function \(f:V(G)\rightarrow \{1,2,\ldots,k\},\) for some positive integer \(k\) such that ...
I Nengah Suparta +3 more
doaj +1 more source
Partitions and Edge Colourings of Multigraphs [PDF]
The Electronic Journal of Combinatorics, 2008 Erdős and Lovász conjectured in 1968 that for every graph $G$ with $\chi(G)>\omega(G)$ and any two integers $s,t\geq 2$ with $s+t=\chi(G)+1$, there is a partition $(S,T)$ of the vertex set $V(G)$ such that $\chi(G[S])\geq s$ and $\chi(G[T])\geq t$. Except for a few cases, this conjecture is still unsolved.
Kostochka, Alexandr V. +1 more
openaire +2 more sources