On parameters related to strong and weak domination in graphs

AbstractLet G be a graph. Then μ(G)⩽|V(G)|−δ(G) where μ(G) denotes the weak or independent weak domination number of G and μ(G)⩽|V(G)|−Δ(G) where μ(G) denotes the strong or independent strong domination number of G. We give necessary and sufficient conditions for equality to hold in each case and also describe specific classes of graphs for which equality holds. Finally, we show that the problems of computing iw and ist are NP-hard, even for bipartite graphs

On Strong Domination Number of Graphs

A subset S of a vertex set V is called a dominating set of graph G if every vertex of V -S is dominated by some element of set S. If e is an edge with end vertices u and v and degree of u is greater than or equal to degree of v then we say u strongly dominates v. If every vertex of V - S is strongly dominated by some vertex of S then S is called strong dominating set. The minimum cardinality of a strong dominating set is called the strong domination number of graph. We investigate strong domination numbers of some graphs and study related parameter