Sufficient conditions for the existence of positive periodic solutions of a class of neutral delay models

摘要

By using the theory of coincidence degree, the existence of positive periodic solutions is studied for the neutral model with periodic delaysN′(t)=N(t)a(t)−β(t)N(t)−∑i=1nbi(t)N(t−τi(t))−∑i=1nci(t)N′(t−γi(t)).Our results extend and improve existing results, and have further applications in population dynamics.