Radio harmonic mean labeling of some star related graphs

A radio harmonic mean labeling of a connected graph G is a one to one map f from the vertex set V(G) to the set of natural numbers N such that for two distinct vertices u and v of G, d(u,v)+[ 2f(u)f(v)f(u)+f(v) ]≥1+diam(G). The radio harmonic mean number of f, rhmn(f) is the maximum number assigned to any vertex of G. The radio harmonic mean number of G, rhmn(G) is the minimum value of rhmn(f) taken over all radio harmonic mean labeling f of G. In this paper we have determined the radio harmonic mean number of some star related graphs.