“…For example, when V is radially symmetric, it is natural to look for radially symmetric solutions, see [36,42]. On the other hand, after the paper of Rabinowitz [33] where the potential V is assumed to be coercive, several different assumptions are adopted in order to obtain existence and multiplicity results (see [6,9,22,39,40]). For the case s = 1, problem (1.1) becomes…”