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Covering Two-Edge-Coloured Complete Graphs with Two Disjoint Monochromatic Cycles

Published online by Cambridge University Press:  01 July 2008

PETER ALLEN*
Affiliation:
Department of Mathematics, London School of Economics, Houghton Street, London WC2A 2AE, UK (e-mail: p.d.allen@lse.ac.uk)

Abstract

In 1998 Łuczak Rödl and Szemerédi [7] proved, by means of the Regularity Lemma, that there exists n0 such that, for any nn0 and two-edge-colouring of Kn, there exists a pair of vertex-disjoint monochromatic cycles of opposite colours covering the vertices of Kn. In this paper we make use of an alternative method of finding useful structure in a graph, leading to a proof of the same result with a much smaller value of n0. The proof gives a polynomial-time algorithm for finding the two cycles.

Type
Paper
Copyright
Copyright © Cambridge University Press 2008

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References

[1]Erdős, P., Gyárfás, A. and Pyber, L. (1991) Vertex coverings by monochromatic cycles and trees. J. Combin. Theory Ser. B 51 9095.CrossRefGoogle Scholar
[2]Erdős,, P. and Szekeres, G. (1935) A combinatorial problem in geometry. Compos. Math. 2 464470.Google Scholar
[3]Gyárfás, A. (1983) Vertex coverings by monochromatic paths and cycles. J. Graph Theory 7 131135.CrossRefGoogle Scholar
[4]Gyárfás, A., Ruszinkó, M.Sárközy, G. N. and Szemerédi, E. (2006) An improved bound for the monochromatic cycle partition number. J. Combin. Theory Ser. B 96 855873.CrossRefGoogle Scholar
[5]Komlós, J., Sárközy, G. N. and Szemerédi, E. (1997) Blow-up lemma. Combinatorica 17 109123.CrossRefGoogle Scholar
[6]Lehel, J. Private communication.Google Scholar
[7]Łuczak, T., Rödl, V. and Szemerédi, E. (1998) Partitioning two-coloured complete graphs into two monochromatic cycles. Combin. Probab. Comput. 7 423436.CrossRefGoogle Scholar
[8]Szemerédi, E. (1976) Regular partitions of graphs. In Problèmes Combinatoires et Théorie des Graphes, Vol. 260 of Colloques Internationaux CNRS, pp. 399401.Google Scholar