“…The existence, nonexistence and/or multiplicity of positive solutions to problem (P λ ) have been studied extensively in the literature; see, for example, [1,2,5,6,8,9,[11][12][13][14][15][17][18][19][20][21][22][23][24][25] and the references therein. In many previous studies, the nonlinear function f (x, s)/s p−1 was assumed to be nonincreasing in s, and under this condition, it can be shown that problem (P λ ) has at most one positive solution (see, e.g., [1,6,8,9,22]).…”