Existence of periodic solutions for a kind of second-order neutral functional differential equation

摘要

By means of the continuation theorem of coincidence degree theory, we study a kind of second-order neutral functional differential equation as followsd2dt2u(t)−∑j=1ncju(t−rj)=f(u(t))u′(t)+α(t)g(u(t))+∑j=1nβj(t)g(u(t−γj(t)))+p(t).Some new results on the existence of periodic solutions are obtained.