摘要
Abstract This paper gives new sufficient conditions for the existence of periodic solutions of a second order non-autonomous differential system by using Mawhin's coincidence degree theory and Brousk's theorem. These results substantially extend and improve the corresponding results in the literatures [1,6,7].
Abstract This paper gives new sufficient conditions for the existence of periodic solutions of a second order non-autonomous differential system by using Mawhin's coincidence degree theory and Brousk's theorem. These results substantially extend and improve the corresponding results in the literatures [1,6,7].
