%0 Journal Article
	%A Changjin Xu and  Qianhong Zhang
	%D 2011
	%J International Journal of Mathematical and Computational Sciences
	%B World Academy of Science, Engineering and Technology
	%I Open Science Index 52, 2011
	%T Positive Periodic Solutions in a Discrete Competitive System with the Effect of Toxic Substances
	%U https://publications.waset.org/pdf/15619
	%V 52
	%X In this paper, a delayed competitive system with the effect of toxic substances is investigated. With the aid of differential equations with piecewise constant arguments, a discrete analogue of continuous non-autonomous delayed competitive system with the effect of toxic substances is proposed. By using Gaines and Mawhin,s continuation theorem of coincidence degree theory, a easily verifiable sufficient condition for the existence of positive solutions of difference equations is obtained.

	%P 649 - 653