In this paper we consider the following parameters: IR(G), the upper irredundance number, which is the order of the largest maximal irredundant set, I'(G), the upper domination number, which is the order of the largest minimal dominating set and /3(G), the independence number, which is the order of
Upper domination and upper irredundance perfect graphs
β Scribed by Gregory Gutin; Vadim E. Zverovich
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 534 KB
- Volume
- 190
- Category
- Article
- ISSN
- 0012-365X
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β¦ Synopsis
Let /~(G), F(G) and IR(G) be the independence number, the upper domination number and the upper irredundance number, respectively. A graph G is called
In this paper, we present a characterization of F-perfect graphs in terms of a family of forbidden induced subgraphs, and show that the class of F-perfect graphs is a subclass of IR-perfect graphs and that the class of absorbantly perfect graphs is a subclass of F-perfect graphs. These results imply a number of known theorems on F-perfect graphs and IR-perfect graphs. Moreover, we prove a sufficient condition for a graph to be F-perfect and IR-perfect which improves a known analogous result.
π SIMILAR VOLUMES
## Abstract Let Ο be any of the domination parameters __ir__ Ξ³, __i__, Ξ², Ξ or __IR__. The graph __G__ is Οβ__critical__ (Ο^+^β__critical__) if the removal of any vertex of __G__ causes Ο(__G__) to decrease (increase). We show that the classes of __IR__βcritical and Ξβcritical graphs coincide, and
Let Ξ²(G) and Ξ(G) be the independence number and the upper domination number of a graph G, respectively. A graph G is called Ξ-perfect if Ξ²(H) = Ξ(H), for every induced subgraph H of G. The class of Ξ-perfect graphs generalizes such well-known classes of graphs as strongly perfect graphs, absorbantl
Necessary and sufficient conditions are established for the existence of a graph whose upper and lower domination, independence and irredundance numbers are six given positive integers. This result shows that the only relationships between these six parameters which hold for all graphs and which do
## Abstract A set __S__ of vertices in a graph __G__ is a total dominating set of __G__ if every vertex of __G__ is adjacent to some vertex in __S__ (other than itself). The maximum cardinality of a minimal total dominating set of __G__ is the upper total domination number of __G__, denoted by Ξ~__