Least domination in a graph
β Scribed by Odile Favaron
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 357 KB
- Volume
- 150
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
The least domination number 7L of a graph G is the minimum cardinality of a dominating set of G whose domination number is minimum. The least point covering number ~L of G is the minimum cardinality of a total point cover (point cover including every isolated vertex of G) whose total point covering number is minimum. We prove a conjecture of Sampathkumar saying that ~L ~<-~n in every connected graph of order n~2. We disprove another one saying that YL <~L in every graph but instead of it, we establish the best possible inequality 7L <~ 3~L-Finally, in relation with the minimum cardinality 7t of a dominating set without isolated vertices (total dominating set), we prove that the ratio 7L/Tt can be in general arbitrarily large, but 9 if we restrict ourselves to the class of trees. remains bounded by ~" Research partially supported by PRC Mathlnfo.
π SIMILAR VOLUMES
In a graph G, a set X is called a stable set if any two vertices of X are nonadjacent. A set X is called a dominating set if every vertex of V-X is joined to at least one vertex of X. A set Xis called an irredundant set if every vertex of X, not isolated in X, has at least one proper neighbor, that
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
## Abstract Let Ξ³(__G__) be the domination number of a graph __G__. Reed 6 proved that every graph __G__ of minimum degree at least three satisfies Ξ³(__G__)ββ€β(3/8)|__G__|, and conjectured that a better upper bound can be obtained for cubic graphs. In this paper, we prove that a 2βedgeβconnected cu
The vertices of the queem;' graph {~, are the squares of an n Γ n chessboard and two squares are adjacent ifa queen placed on one covers the other. It is shown that the domination num;~'r of Q. is at most 31n/54 + O(1), that Q. possesses minimal dominating sets of cardina~tty 5n/2 -O(l) and that the