Identifying codes of corona product graphs

For a vertex x of a graph G, let N-G vertical bar x vertical bar be the set of x with all of its neighbors in G. A set C of vertices is an identifying code of G if the sets N-G[X] boolean AND C are nonempty and distinct for all vertices x. If G admits an identifying code, we say that G is identifiable and denote by gamma(ID)(G) the minimum cardinality of an identifying code of G. In this paper, we study the identifying code of the corona product H circle dot G of graphs H and G. We first give a necessary and sufficient condition for the corona product H circle dot G to be identifiable, and then express gamma(ID)(H circle dot G) in terms of gamma(ID)(G) and the (total) domination number of H. Finally, we compute gamma(ID)(H circle dot G) for some special graphs G. (C) 2013 Elsevier B.V. All rights reserved.