Periodic boundary value problem for the first order impulsive functional differential equations (Q875391)

Assuming the existence of a lower solution \(\alpha\) and an upper solution \(\beta\) such that \(\alpha\leq\beta\) with the usual order, the monotone iterative technique is used to show that the periodic boundary value problem for a class of first-order differential equations with delay and impulses has the minimal and the maximal solutions in \([\alpha,\beta]\). For it, a new comparison result is proved.