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K5-Subdivisions in Graphs

Published online by Cambridge University Press:  12 September 2008

Carsten Thomassen
Affiliation:
Mathematical Institute, Technical University of Denmark, DK-2800 Lyngby, Denmark

Abstract

In 1964 Dirac conjectured that every graph with n vertices and at least 3n − 5 edges contains a subdivision of K5 We prove a weakened version with 7/2;n − 7 instead of 3n − 5. We prove that, for any prescribed vertex νo, the subdivision can be found such that νo is not one of the five branch vertices. This variant of Dirac's problem, which was suggested by the present author in 1973, is best possible in the sense that 7/2;n − 7 cannot be replaced by 7/2;n − 15/2;.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1996

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References

[1]Bondy, J. A. and Lovász, L. (1981) Cycles through specified vertices of a graph. Combinatoric 1 114140.CrossRefGoogle Scholar
[2]Bollobás, B. (1978) Extremal Graph Theory, Academic Press.Google Scholar
[3]Bollobás, B. and Thomason, A. G.Proof of a conjecture of Mader, Erdös and Hajnal on topological complete subgraphs, Combinatorica, to appear.Google Scholar
[4]Dirac, G. A. (1964) Homomorphism theorems for graphs, Math. Ann. 153 6980.CrossRefGoogle Scholar
[5]Komlós, J. and Szemerédi, E.Topological cliques in graphs, Combinatorics, Probability and Computing, to appear.Google Scholar
[6]Lovász, L. (1974) Problem 5, Period. Math. Hungar. 4 82.Google Scholar
[7]Perfect, H. (1968) Applications of Menger's theorem, J. Math. Analysis Appl. 22 96111.CrossRefGoogle Scholar
[8]Seymour, P. D. (1980) Disjoint paths in graphs, Discrete Math. 29 292309.CrossRefGoogle Scholar
[9]Thomassen, C. (1974) Some homeomorphism properties of graphs, Math. Nachr. 64 119133.CrossRefGoogle Scholar
[10]Thomassen, C. (1980) 2-linked graphs, Euro. J. Combinatorics 1 371378.CrossRefGoogle Scholar
[11]Thomassen, C. (1984) Plane representations of graphs, in Progress in Graph Theory, Bondy, J. A. and Murty, U. S. R., eds., Academic Press, pp. 4369.Google Scholar
[12]Thomassen, C. (1988) Paths circuits and subdivisions, in Selected Topics in Graph Theory, Beineke, L. W. and Wilson, R. J., eds., Academic Press, pp. 97131.Google Scholar