【摘要】 本文给出了一类滞后型泛函微分方程有一个周期解的四个充分性定理，其结果明显地优于著名的Ｙｏｓｈｉｚａｗａ周期解定理，最后给出了应用实例。更多还原

【Abstract】 In this paper. the retarded functional differential equation are considered. We obtain four existence theorems of periodc solutions of it. The application of these theorems are convenient and efficient. and the theorem of this paper is better than the well-known Yoshizawa’s periodic solution theorem. A feedback system is discussed in detail and a sufficient condition of guaranteeing the existence of an ω-Periodic motion of the system is got by applying these theo-rems in this paper.更多还原