If the edges of a complete graph K,., m/> 4, are painted two colours so that monochromatic K " graphs are connected, then there exists an increasing sequence ( n)n~4 of complete subgraphs whose monochromatic subgraphs are also connected. For more than two colours this is not true, but an analogous f
The Existence of Exactlym-Coloured Complete Subgraphs
β Scribed by Alan Stacey; Peter Weidl
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 842 KB
- Volume
- 75
- Category
- Article
- ISSN
- 0095-8956
No coin nor oath required. For personal study only.
β¦ Synopsis
Given a graph G, its edges are said to be exactly x-coloured if we have a surjective map from the edges to some set of colours of size x. Erickson considered the following statement which he denoted P(c, m): if the edges of K | the complete graph on vertex set N are exactly c-coloured, then there exists an infinite complete subgraph of K | whose edges are exactly m-coloured. Ramsey's Theorem states that P(c, m) is true for m=1 and all c 1, and can easily be used to show that P(c, m) holds when m=2 and c 2. Erickson conjectured that P(c, m) is false whenever c>m 3. We prove that given m 3 there exists an integer C(m) such that P(c, m) is false for all c C(m).
π SIMILAR VOLUMES
Fisher, D.C. and J. Ryan, Bounds on the number of complete subgraphs, Discrete Mathematics 103 (1992) 313-320. Let G be a graph with a clique number w. For 1 s s w, let k, be the number of complete j subgraphs on j nodes. We show that k,,, c (j~l)(kj/(~))u""'. This is exact for complete balanced w-
It is shown that if three vertices of the graph c?(l)) of a convex 3-polytope P are chosen, then G(P) contains a refinement of the complete graph C,, on four vertices, for which the three chosen vertices are principal (that is, correspond to vertices of C, in the refinement.. In general, all four ve
## Abstract In this paper, we consider forbidden subgraphs which force the existence of a 2βfactor. Let \documentclass{article}\footskip=0pc\pagestyle{empty}\begin{document}${\cal G}$\end{document} be the class of connected graphs of minimum degree at least two and maximum degree at least three, an