Dichotomy condition and periodic solutions for two nonlinear neutral systems (Q2171686)

In the paper, the existence of periodic solutions of two neutral functional differential systems is studied. Using standard fixed-point theorems, the authors prove four existence theorems which claim that if the corresponding linear system has an integrable dichotomy, then, under quite restrictive hypotheses concerning non-linearities, the systems considered have at least one (resp. a unique) periodic solution.