Variations of Hale's channel assignment problem, the L(j, k)-labeling problem and the radio labeling problem require the assignment of integers to the vertices of a graph G subject to various distance constraints. The λj,k-number of G and the radio number of G are respectively the minimum span among all L(j, k)-labelings, and the minimum span plus 1 of all radio labelings of G (defined in the Introduction). In this paper, we establish the λj,k-number of ∏qi=1 Kti for pairwise relatively prime integers t1 < t2 < ... < tq, t1 ≥ 2. We also show the existence of an infinite class of graphs G with radio number |V(G)| for any diameter d(G).
