“…Motivated by the fact that the fractional Laplacian appears in a lot of application, several authors have dedicated a special attention for problems involving this important operator. The reader can find some recent results in Alves and Miyagaki [1,2], Brändler, Colorado and Sánchez [10], Cabré and Sire [14], Caffarelli and Silvestre [15], Chang and Wang [16], Cotsiolis and Tavoularis [18], Dávila, del Pino and Wei [19], Dipierro, Palatucci and Valdinoci [21], Fall, Mahmoudi and Valdinoci [25], Felmer, Quaas and Tan [26], Palatucci and Pisante [30], Secchi [32], Silvestre [33] and their references. In the most part of the above references the variational method was used to show the existence of solution.…”