“…Also, several papers on the topic of dynamical systems with (upper semicontinuous) set-valued functions have appeared recently, see [BEGK,CP,LP,LYY,LWZ,KN,KW,MRT,R,SS,SS2], where more references may be found. However, there is not much known of such dynamical systems and therefore, there are many properties of such set-valued dynamical systems that are yet to be studied.…”