On the (2,2)-domination number of trees
You Lu, Xinmin Hou, Jun-Ming Xu (2010)
Discussiones Mathematicae Graph Theory
Similarity:
Let γ(G) and denote the domination number and (2,2)-domination number of a graph G, respectively. In this paper, for any nontrivial tree T, we show that . Moreover, we characterize all the trees achieving the equalities.