“…In recent years, there has been much progress on the qualitative properties of difference equations and a lot of interesting results have been worked out, which included results on stability [5], attractivity [14], periodic solutions [3,6,7,8,9,11,17,18,27], homoclinic orbits [4,10,13,21,22,23,24,26,28], boundary value problems [19,20,25] and other topics [1,2,12].…”