Existence of Many and Infinitely Many Periodic Solutions for Some Types of Differential Delay Equations

时滞微分方程多个及无穷多个周期解的存在性

J.Kaplan and J.Yorke's method is extended to establish the exis- tence of many and infinitely many periodic solutions for the DDEs (t) =±f(x(t-1))±f(x(t-2))and (t)=±f(x(t-1).

研究时滞微分方程 x(t)=±f(x(t—1))±f(x(t—2))及 x(t)=±f(x(t—1))周期解的存在性,给出了存在多个及无穷多个周期解的充分条件,结果是新的。