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Lovász Conjecture


The Lovász conjecture (in its most widely encountered form) states that without exception, every connected vertex-transitive graph is traceable (Lovász 1970; cf. Gould 1991; Godsil and Royle 2001, p. 45; Mütze 2024).

Amusingly, Babai (1979, 1996) published a directly contradictory conjecture.

A similar conjecture attributed to Thomassen (Bermond 1979, Gould 1991) asserts that, with exactly five exceptions (the nonhamiltonian vertex-transitive graph), every vertex-transitive graph is Hamiltonian.

While the Lovász conjecture has subsequently been verified for several special orders and classes, both conjectures remain open.


See also

Hamiltonian Cycle, Hamiltonian Graph, Hamiltonian Path, Nonhamiltonian Vertex-Transitive Graph, Traceable Graph, Vertex-Transitive Graph

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References

Babai, L. Problem 17 in "Unsolved Problems." In Summer Research Workshop in Algebraic Combinatorics. Burnaby, Canada: Simon Fraser University, Jul. 1979.Babai, L. "Automorphism Groups, Isomorphism, Reconstruction." Ch. 27 in Handbook of Combinatorics, Vol. 2 (Ed. R. L. Graham, M. Grötschel, M.; and L. Lovász). Cambridge, MA: MIT Press, pp. 1447-1540, 1996.Bermond, J.-C. "Hamiltonian Graphs." Ch. 6 in Selected Topics in Graph Theory (Ed. L. W. Beineke and R. J. Wilson). London: Academic Press, pp. 127-167, 1979.Godsil, C. and Royle, G. "Hamilton Paths and Cycles." C§3.6 in Algebraic Graph Theory. New York: Springer-Verlag, pp. 45-47, 2001.Gould, R. J. "Updating the Hamiltonian Problem--A Survey." J. Graph Th. 15, 121-157, 1991.Lovász, L. Problem 11 in "Combinatorial Structures and Their Applications." In Proc. Calgary Internat. Conf. Calgary, Alberta, 1969. London: Gordon and Breach, pp. 243-246, 1970.Mütze, T. "On Hamilton Cycles in Graphs Defined by Intersecting Set Systems." Not. Amer. Soc. 74, 583-592, 2024.

Cite this as:

Weisstein, Eric W. "Lovász Conjecture." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/LovaszConjecture.html

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