On the r-domination number of a graph
โ Scribed by Jerrold R. Griggs; Joan P. Hutchinson
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 468 KB
- Volume
- 101
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
โฆ Synopsis
For r > 0, let the r-domination number of a graph, d,, be the size of a smallest set of vertices such that every vertex of the graph is within distance r of a vertex in that set. This paper contains proofs that every graph with a spanning tree with at least n/2 leaves has d, s n/(2r); this compares with the easy upper bound of [n/(2r + 1)1 for graphs with Hamiltonian paths.
๐ SIMILAR VOLUMES
For a graph G, the definitions of doknation number, denoted y(G), and independent domination number, denoted i(G), are given, and the following results are obtained: oorollrrg 1. For any graph G, y(L(G)) = i@(G)), where Z,(G) is the line graph of G. (This $xh!s t.lic rtsult ~(L(T))~i(L(T)), h w ere
Upper bounds for u + x and ax are proved, where u is the domination number and x the chromatic number of a graph.
The kdomination number of a graph G, y k ( G ) , is the least cardinality of a set U of verticies such that any other vertex is adjacent to at least k vertices of U. We prove that if each vertex has degree at least k. then YAG) 5 kp/(k + 1).
In this communication the domination number of the cross product of an elementary path with the complement of another path is exactly determined and some inequalities for general cases are deduced. The paper ends with a Vizing-like conjecture relating the domination number of the cross product of G
Topp, J. and L. Volkmann, On graphs wi',h equal domination and independent domination number, Discrete Mathematics 96 (1991) 75-80. Allan and Laskar have shown that Kt.s-free graphs are graphs with equal domination and independent domination numbers. In this paper new classes of graphs with equal d