Positive periodic solutions for a class of delay differential equations

摘要

In this paper, we employ fixed point theorem and functional equation theory to study the existence of positive periodic solutions of the delay differential equationx′(t)=α(t)x(t)-β(t)x2(t)+γ(t)x(t-τ(t))x(t).Moreover, new explicit conditions for the related population growth models are also given.