Asymptotic Behavior and Periodisity of Solutions of Differdntial Equations

村上-山本[3][13]，和田-山本[4][11]，齐藤-山本[6][10]，和Ohe-Yamamoto[7][15]是许多结果的推广.由Nagabuchi-Yamamoto[2]得到的二阶非线性微分方程解的振动性定理是Yen在1986年得到的结果的推广.Saito-Yamamoto[5]和Sugie-Yamamoto[14]讨论了非线性系统周期解的存在性，得到了新的结果.在Hirano-Yamamoto[1][12]中证明了线性方程周期解的唯一性定理.在Saito-Yamamoto[8][9]中证明了拟线性系统周期解的存在定理在Saito-Yamamoto[16]中讨论了周期系统，得到了Cronin定理的推广，Hale和Mawhin的结果。上述结果都是许多作者的结果的推广。纵观上述文章，可以认为我们几乎所有的目的都已经实现了。

Stability therorems obtained in articles by Murakami-Yamamoto [3] [13], Wada-Yamamoto [4] [11], Saito-Yamamoto [6] [10], and Ohe-yamamoto [7] [15] are extensitions of many results.Oscillation theorems for second order nonlinear differential equations by Nagabuchi-Yamamoto [2] are extensions of those obtained by yan in 1986.On the existence of periodic solutions of nonlinear systems are considered in Saito-Yamamoto [5] and Sugie-Yamamoto [14] and had new results.Uniqueness theorems of periodic solutions of Lineard equations are proved in Hirano-Yamamoto [1] [12].Existence theorems of solutions for quasilinear systems are proved in Saito-Yamamoto [8] [9].Continuous dependence of periodic solutions for periodic systems are discussed in Saito-Yamamoto [16] and obtained extensions of the theorems due to Cronin, Hale and Mawhin respectively.All results above are extensions of those obtained by many authors. Throughout the above articles, it can be considered that almost all of our purpose had been achieved.