Permanence of a discrete -species cooperation system with time-varying delays and feedback controls

In this paper, a discrete n -species cooperation system with time-varying delays and feedback controls is considered. By using the techniques of [Y.H. Fan, L.L. Wang, Permanence for a discrete model with feedback control and delay, Discrete Dyn. Nat. Soc. (2008) Article ID 945109], sufficient conditions are obtained for the permanence of the system, which improve a result given in [F.D. Chen, Permanence of a discrete N -species cooperation system with time delays and feedback controls, Appl. Math. Comput. 186 (2007) 23–29].