【摘要】 使用临界点理论研究以下二阶系统{(t)+q(t)ù(t)=⊿F(t,u(t))/u(0)-u(T)=ù(0)-eQ(T)ù(T)=0,a.e.t∈[0,T]的周期解的存在性。在非线性项F(t,x)=F1(t,x)+F2(t,x)满足条件(A)及F1(t,x),F2(t,x)分别满足一定条件下,通过使用鞍点定理获得了一个新的周期解的存在性定理。更多还原

【Abstract】 By using critical point theory, the purpose of this paper is to study the existence of periodic solutions of the following second order systems{(t)+q(t)ù(t)=⊿F(t,u(t))/u(0)-u(T)=ù(0)-eQ(T)ù(T)=0,a.e.t∈[0,T].When the nonlinear term F(t,x)=F1(t,x)+F2(t,x) satisfies condition(A) and F1(t,x),F2(t,x) satisfy many conditions. One new existence theorem of periodic solution is obtained by the saddle point theorem.更多还原