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COMBINATORICA
Article . 1981 . Peer-reviewed
License: Springer TDM
Data sources: Crossref
image/svg+xml Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Closed Access logo, derived from PLoS Open Access logo. This version with transparent background. http://commons.wikimedia.org/wiki/File:Closed_Access_logo_transparent.svg Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao
zbMATH Open
Article . 1981
Data sources: zbMATH Open
DBLP
Article . 1981
Data sources: DBLP
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On the conjecture of hajós

On the conjecture of Hajos
Authors: Paul Erdös; Siemion Fajtlowicz;

On the conjecture of hajós

Abstract

\textit{G.Hajós} [Wiss. Z. Martin-Luther-Univ. Halle-Wittenberg, Math.-Naturw. Reihe 10, 113-117 (1961; Zbl 0094.17602), pp. 116-117] conjectured that every \(s\)-chromatic graph contains a subdivision of \(K_s\), the complete graph on \(s\) vertices. This conjecture was disproved ins a paper by \textit{P.A.Catlin} [J. Comb. Theory, Ser. B 26, 268-274 (1979; Zbl 0385.05033)]. In the present paper it is shown by probabilistic methods that the Hajós conjecture fails for almost all graphs. More precisely, let \(G=G(n)\) be a graph of \(n\) vertices. Denote by \(\chi(G)\) the chromatic number of \(G\) and by \(\sigma(G)\) the largest integer \(\ell\) such that \(G\) contains a subdivision of \(K_{\ell}\). Put \(H(G)=\chi(G)/\sigma(G)\) and \(H(n)=\max_{G(n)}H(G(n))\) (hence, the Hajós conjecture says \(H(n)=1\)). In the present paper it is shown that there exists an absolute constant \(c\) such that \(H(n)> C\sqrt n/\log n\) holds for almost all labelled graphs with \(n\) vertices.

Related Organizations
Keywords

labelled graphs, Coloring of graphs and hypergraphs, Combinatorial probability, chromatic number, subdivision, Random graphs (graph-theoretic aspects), s-chromatic graph

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
35
Top 10%
Top 1%
Average
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