منابع مشابه
Total restrained domination in trees
Let G = (V,E) be a graph. A set S ⊆ V is a total restrained dominating set if every vertex is adjacent to a vertex in S and every vertex of V − S is adjacent to a vertex in V − S. The total restrained domination number of G, denoted by γtr(G), is the smallest cardinality of a total restrained dominating set of G. We show that if T is a tree of order n, then γtr(T ) ≥ d(n + 2)/2e. Moreover, we s...
متن کاملTrees with Equal Restrained Domination and Total Restrained Domination Numbers
For a graph G = (V,E), a set D ⊆ V (G) is a total restrained dominating set if it is a dominating set and both 〈D〉 and 〈V (G)−D〉 do not have isolated vertices. The cardinality of a minimum total restrained dominating set in G is the total restrained domination number. A set D ⊆ V (G) is a restrained dominating set if it is a dominating set and 〈V (G) − D〉 does not contain an isolated vertex. Th...
متن کاملOn weak and restrained domination in trees
In a graph G = (V,E) a vertex is said to dominate itself and all its neighbours. A weak dominating set is a set S ⊆ V where for every vertex u not in S there is a vertex v of S adjacent to u with dG(v) 6 dG(u) . A restrained dominating set is a set S ⊆ V where every vertex in V − S is adjacent to a vertex in S as well as another vertex in V − S . The weak domination number γw(G) (resp. restrain...
متن کاملA Note on Restrained Domination in Trees
Let G = (V,E) be a graph. A set S ⊆ V is a restrained dominating set if every vertex not in S is adjacent to a vertex in S and to a vertex in V − S. The restrained domination number of G, denoted by γr(G), is the smallest cardinality of a restrained dominating set of G. It is known that if T is a tree of order n, then γr(T ) ≥ d(n+2)/3e. In this note we provide a simple constructive characteriz...
متن کاملTotal restrained domination numbers of trees
For a given connected graphG= (V ,E), a setDtr ⊆ V (G) is a total restrained dominating set if it is dominating and both 〈Dtr〉 and 〈V (G)−Dtr〉 do not contain isolate vertices. The cardinality of the minimum total restrained dominating set in G is the total restrained domination number and is denoted by tr(G). In this paper we characterize the trees with equal total and total restrained dominati...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 2000
ISSN: 0012-365X
DOI: 10.1016/s0012-365x(99)00036-9