In this paper we discuss the problem -DELTAu + c2u = u(p) + muf(x), u > 0, u is-an-element-of H-1(R(N)), n > 2. ((*)mu) We show that for c > 0 there exists a positive constant mu* such that (*)mu possesses at least one solution if mu is-an-element-of (0, mu*) and no solutions if mu > mu*. Furthermore,there exists a positive constant mu** less-than-or-equal-to mu* such that (*)mu possesses at least two solutions if mu is-an-element-of (0, mu**), 2 < N < 6. For N greater-than-or-equal-to 6, mu is-an-element-of (0, mu**), we show that problem (*)mu possesses a uniqu...
