DMGT

ISSN 1234-3099 (print version)

ISSN 2083-5892 (electronic version)

https://doi.org/10.7151/dmgt

Discussiones Mathematicae Graph Theory

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Discussiones Mathematicae Graph Theory

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Discussiones Mathematicae Graph Theory 25(3) (2005) 251-259
DOI: https://doi.org/10.7151/dmgt.1278

DOMINATION AND LEAF DENSITY IN GRAPHS

Anders Sune Pedersen

Department of Mathematics, Aalborg University
Fredrik Bajers Vej 7G, DK 9220 Aalborg, Denmark
e-mail: asp@math.auc.dk

Abstract

The domination number γ(G) of a graph G is the minimum cardinality of a subset D of V(G) with the property that each vertex of V(G)−D is adjacent to at least one vertex of D. For a graph G with n vertices we define ε(G) to be the number of leaves in G minus the number of stems in G, and we define the leaf density ζ(G) to equal ε(G)/n. We prove that for any graph G with no isolated vertex, γ(G) ≤ n(1− ζ(G))/2 and we characterize the extremal graphs for this bound. Similar results are obtained for the total domination number and the partition domination number.

Keywords: bounds; domination number; leaves; partioned domination; total domination number.

2000 Mathematics Subject Classification: Primary 05C69, 05C35; Secondary 05C75.

References

[1] R.C. Brigham, J.R. Carrington and R.P. Vitray, Connected graphs with maximum total domination number, J. Combin. Math. Combin. Comput. 34 (2000) 81-95.
[2] E.J. Cockayne, R.M. Dawes and S.T. Hedetniemi, Total domination in graphs, Networks 10 (1980) 211-219, doi: 10.1002/net.3230100304.
[3] J.F. Fink, M.S. Jacobson, L.F. Kinch and J. Roberts, On graphs having domination number half their order, Period. Math. Hungar. 16 (1985) 287-293, doi: 10.1007/BF01848079.
[4] M.R. Garey and D.S. Johnson, Computers and Intractability: A Guide to the Theory of NP-completeness (Freeman, New York, 1979).
[5] B.L. Hartnell and P.D. Vestergaard, Partitions and domination in a graph, J. Combin. Math. Combin. Comput. 46 (2003) 113-128.
[6] T.W. Haynes, S.T. Hedetniemi and P.J. Slater, Fundamentals of domination in graphs (Marcel Dekker, Inc., 1998).
[7] A.M. Henning and P.D. Vestergaard, Domination in partitioned graphs with minimum degree two (Manuscript, 2002).
[8] O. Ore, Theory of Graphs (Amer. Math. Soc. Colloq. Publ., 1962).
[9] C. Payan and N.H. Xuong, Domination-balanced graphs, J. Graph Theory 6 (1982) 23-32, doi: 10.1002/jgt.3190060104.
[10] S.M. Seager, Partition dominations of graphs of minimum degree 2, Congr. Numer. 132 (1998) 85-91.
[11] Z. Tuza and P.D. Vestergaard, Domination in partitioned graphs, Discuss. Math. Graph Theory 22 (2002) 199-210, doi: 10.7151/dmgt.1169.

Received 19 May 2003
Revised 1 October 2003


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