Positive periodic solutions for a class of second-order differential equations with state-dependent delays

Abstract

In this paper, we consider a class of second order differential equations with iterative source term. The mainresults are obtained by virtue of a Krasnoselskii fixed point theorem and some useful properties of a Green’s functionwhich allows us to prove the existence of positive periodic solutions. Finally, an example is included to illustrate thecorrectness of our results.