A class of graphs is hereditary if it is closed under taking induced subgraphs. Classes associated with graph representations have "composition sequences" and we show that this concept is equivalent to a notion of "amalgamation" which generalizes disjoint union of graphs. We also discuss how general
On the Size of Hereditary Classes of Graphs
β Scribed by E.R Scheinerman; J Zito
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 912 KB
- Volume
- 61
- Category
- Article
- ISSN
- 0095-8956
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β¦ Synopsis
A hereditary property of graphs is a class of graphs which is closed under taking induced subgraphs. For a hereditary property (\mathscr{P}), let (\mathscr{P}{n}) denote the set of (\mathscr{P}) graphs on (n) labelled vertices. Clearly we have (0 \leqslant\left|\mathscr{P}{n}\right| \leqslant 2^{n(n-1) / 2}), but much more can be said. Our main results show that the growth of (\left|\mathscr{P}{n}\right|) is far from arbitrary and that certain growth rates are impossible. For example, for no property (\mathscr{P}) does one have (\left|\mathscr{P}{n}\right| \sim \log n . \quad 1994) Academic Press, Inc.
π SIMILAR VOLUMES
In this paper we introduce the concept of a boundary class, which is a helpful tool for classiΓΏcation of hereditary classes of graphs according to the complexity of the independent set problem. It is shown that in a class X deΓΏned by a ΓΏnite set of forbidden induced subgraphs, the problem is NP-hard