“…has attracted considerable attention recently [1,2,7,10,11,12,14,16,17,19,21,25,26], where {f n } ∞ n=0 is a sequence of maps from X to X, with (X, d) being a metric space. Many complex systems of real-world problems in the fields of biology, physics, chemistry and engineering, are indeed non-autonomous, putting the model (1.1) into focus.…”