Abstract
The main aim of this paper is to give some upper and lower bounds for the isoperimetric numbers of graph coverings or graph bundles, with exact values in some special cases. In addition, we show that the isoperimetric number of any covering graph is not greater than that of the base graph. Mohar's theorem for the isoperimetric number of the cartesian product of a graph and a complete graph can be extended to a more general case: The isoperimetric numberi(G × K 2n) of the cartesian product of any graphG and a complete graphK 2n on even vertices is the minimum of the isoperimetric numberi(G) andn, and it is also a sharp lower bound of the isoperimetric numbers of all graph bundles over the graphG with fiberK 2n. Furthermore, ifn ≥ 2i(G) then the isoperimetric number of any graph bundle overG with fibreK n is equal to the isoperimetric numberi(G) ofG.
Similar content being viewed by others
References
Akiyama, J., Avis, D., Chavátal, V., Era, H.: Balancing signed graphs. Discrete Applied Math.3, 227–233 (1981)
Alon, N., Milman, V.D.:λ 1, isoperimetric inequalities for graphs, and superconcentrators. J. Comb. Theory Ser. B38, 73–88 (1985)
Bollobás, B., Leader, I.: An isoperimetric inequality on the discrete torus. SIAM J. Discr. Math.3, 32–37 (1990)
Chae, Y., Kwak, J.H., Lee, J.: Characteristic polynomials of some graph bundles. J. Korean Math. Soc.30, 229–249 (1993)
Cvetković, D.M., Doob, M., Sachs, H.: Spectra of graphs, Academic Press, New York, 1979
Cameron, P.J., Wells, A.L., Jr.: Signatures and signed switching classes. J. Comb. Theory Ser. B40, 344–361 (1986)
Dodziuk, J.: Difference equations, isoperimetric inequality and transience of certain random walks. Trans. Amer. Math. Soc.284, 787–794 (1984)
Gross, J.L., Tucker, T.W.: Generating all graph coverings by permutation voltage assignments. Discrete Math.18, 273–283 (1977)
Gross, J.L., Tucker, T.W.: Topological Graph Theory, Wiley, New York, 1987
Hammer, P.L.: Pseudo-Boolean remarks on balanced graphs. Ser. Internation. Anal. Numér., Suisse36, 69–78 (1977)
Hansen, P.: Labelling algorithms for balance in signed graphs. In: J.C. Bermond et al., eds., Problèmes Combinatoires et Théorie des Graphes (Éditions du C.N.R.S., Paris, 1978), 215–217
Kwak, J.H., Lee, J.: Isomorphism classes of graph bundles. Canad. J. Math.XLII, 747–761 (1990)
Kwak, J.H., Lee, J.: Characteristic polynomials of some graph bundles II. Linear and multilinear algebra32, 61–73 (1992)
Mohar, B.: Isoperimetric inequalities, growth, and the spectrum of graphs. Linear algebra and its applications103, 119–131 (1988)
Mohar, B.: Isoperimetric numbers of graphs. J. Comb. Theory Ser.B 47, 274–291 (1989)
Mohar, B., Pisanski, T., Škoviera, M.: The maximum genus of graph bundles. Europ. J. Comb.9, 215–224 (1988)
Pisanski, T., Shawe-Taylor, J., Varvec, J.: Edge-colorability of graph bundles. J. Comb. Theory Ser. B35, 12–19 (1983)
Varopoulos, N. Th.: Isoperimetric inequalities and Markov chains. J. Funct. Anal.63, 215–239 (1985)
Author information
Authors and Affiliations
Additional information
Partially supported by The Ministry of Education, Korea.
Rights and permissions
About this article
Cite this article
Kwak, J.H., Lee, J. & Sohn, M.Y. Isoperimetric numbers of graph bundles. Graphs and Combinatorics 12, 239–251 (1996). https://doi.org/10.1007/BF01858458
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF01858458