Hostname: page-component-77c89778f8-fv566 Total loading time: 0 Render date: 2024-07-25T01:35:11.975Z Has data issue: false hasContentIssue false

An Efficient Method of Examining all Trees

Published online by Cambridge University Press:  12 September 2008

Ewa Kubicka
Affiliation:
Department of Mathematics, University of Louisville, Louisville, Kentucky 40292, USA

Abstract

In this paper, we present a techique for examining all trees of a given order. Our approach is based on the Beyer and Hedetniemi algorithm for generating all rooted trees of a given order and on the Wright, Richmond, Odlyzko and McKay algorithm for generating all free trees of a given order. In the introduction we describe these algorithms. We also give a precise evaluation of the average number of moves it takes to generate a rooted tree, which improves the upper bound given by Beyer and Hedetniemi. In the second section we present a new method of examining all trees which uses these generating algorithms. The last section contains two applications of the method introduced. The main result of the paper is that the average number of steps required by the proposed algorithm to examine a rooted tree is bounded by a constant independent of the order of a tree.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1996

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

[1]Beyer, T. and Hedetniemi, S. M. (1980) Constant time generation of rooted trees. SI AM J. Comput. 9 706712.CrossRefGoogle Scholar
[2]Chartrand, G. and Lesniak, L. (1988) Graphs and Digraphs, 2nd Edition, Wadsworth, Monterey.Google Scholar
[3]Godsil, C. and McKay, B. (1976) Some computational results on the spectra of graphs. Combinatorial Mathematics IV: Lecture Notes in Mathematics 560, Springer-Verlag, 7392.CrossRefGoogle Scholar
[4]Harary, F. and Palmer, E. M. (1973) Graphical Enumeration, Academic Press.Google Scholar
[5]Jamison, R. E. (1983) On the average number of nodes in a subtree of a tree. J. Combinatorial Theory Ser. B 35 207223.CrossRefGoogle Scholar
[6]Kubicka, E. (1989) The chromatic sum and efficient tree algorithms. PhD Dissertation, Western Michigan University.Google Scholar
[7]Otter, R. (1970) The number of trees. Can. Math. Congress, Montreal.Google Scholar
[8]Polya, G. (1937) Kombinatorische Anzahlbestimmungen fur Gruppen, Graphen und chemische Verbindungen. Acta Math. 68 145154.CrossRefGoogle Scholar
[9]Robinson, R. and Schwenk, A. (1975) The distribution of degrees in a large random tree. Discrete Math. 12 359372.CrossRefGoogle Scholar
[10]Schwenk, A. J. (1973) Almost all trees are cospectral. In: Hlarary, F. (Ed.), New Directions in the Theory of Graphs, Academic Press, 155163.Google Scholar
[11]Wright, R. A., Richmond, B., Odlyzko, A. and McKay, B. D. (1986) Constant time generation of free trees. SIAM J. Comput. 15 540548.CrossRefGoogle Scholar