“…A set S of vertices in a graph G is a dominating set if every vertex not in S is adjacent to a vertex in S. If, in addition, S is an independent set, then S is an independent dominating set, abbreviated ID-set. The independent domination number, denoted i(G), of G is the minimum cardinality of an ID-set in G. The concept of independent domination number of graphs is studied extensively in the literature, for example see [1,2,3,4,5,7,8,9,10,11,13,14,15,16,17,18,19,20]. A survey on independent domination in graphs can be found in [6].…”