THE UNIQUE EXISTENCE OF PERIODIC SOLUTION FOR A CLASS OF ORDINARY DIFFERENTIAL EQUATION SYSTEMS AT RESONANCE
共振下一类常微分方程组周期解的唯一存在性

Early in 1904,Hadamard 1] got the scale implicit function theorem of finite di-mensions.Then it was generalized to infinite dimensions.Here a new proof of this the-orem is given and used to discuss the unique existence of periodic solution for a classof ordinary differential eqcation systems at resonance.