“…, λ n are real constants, F : S → S is a given function, while f : S → S is the unknown function. There exists a rich literature concerning polynomial-like iterative equations (see, for instance, [6,8,[14][15][16][17][18][19]). Especially, we point out here the papers by Zhang et al [19] and by Xu and Zhang [16], dealing with the existence of monotonic or convex solutions to Eq.…”