“…For (1 = 3, Battiti, Bertossi and Bonuccelli [1] found optimal £(1, 1)-colorings for rings, and bidimensional grids, as well as efficient heuristics for geometric graphs. Optimal £(1,1, ..., 1)-colorings, for any positive integer (1, have been proposed by Bertossi and Pinotti [2] When the channel separation constraint is present, the problem has been studied only for small values of (1. The intractability of the £(2, 1)-coloring has been shown by Griggs and Yeh [7] along with bounds on the number of channels for buses, rings and hypercubes.…”