一类二阶泛函微分方程周期解存在性问题

On the Existence of Periodic Solutions for the Second Order Functional Differential Equation

利用重合度理论研究一类二阶泛函微分方程x″(t)+f(t,xt)x^'n+β(t)g(x(t-τt)))=p(t)的周期解问题，本文得到了周期解存在的新的结果．

In this paper, by using the theorem of coincidence degree, the authors study periodic solution to a class of second order functional diffrential equation x'(t) + f(t, x_t)x'' +β(t)g(x(t-T(t))) =p(t). Some new results for the existence of the periodic solution are obtained.