Copyright © 2010 Xuepeng Li and Wensheng Yang. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We propose a discrete model of mutualism with infinite deviating arguments, that is x1(n+1)=x1(n)exp{r1(n)[(K1(n)+α1(n)∑s=0∞J2(s)x2(n−s))/(1+∑s=0∞J2(s)x2(n−s))−x1(n−σ1(n))]},x2(n+1)=x2(n)exp{r2(n)[(K2(n)+α2(n)∑s=0∞J1(s)x1(n−s))/(1+∑s=0∞J1(s)x1(n−s))−x2(n−σ2(n))]}. By some Lemmas, sufficient conditions are obtained for the permanence of the system.