The doubly metric dimension of a connected graph G is the minimum cardinality
of doubly resolving sets in it. It is well known that deciding the doubly
metric dimension of G is NP-complete. The corona product G ? H of two
vertex-disjoint graphs G and H is defined as the graph obtained from G and H
by taking one copy of G and |V(G)| copies of H, then joining the ith vertex
of G to every vertex in the ith copy of H. In this paper some formulae on
the doubly metric dimension of corona product G?H of graphs G and H are
established in terms of the order of G with the adjacency dimension of H and
the doubly metric dimension of K1 ? H, respectively. We determine both sharp
upper and lower bounds on doubly metric dimension of corona product graphs
with disconnected and connected coronas involved, respectively, and
characterize the corresponding extremal graphs. We also characterize all
graphs G of diameter two with doubly metric dimension two. Furthermore, the
exact values are obtained for the doubly metric dimensions of corona product
graphs, being the corona either a path or a cycle.