【摘要】 本文在Banach空间中研究了二阶非线性微分方程的周期边值问题:-u″=f(t,u),u(0)= u(2π),u′(0)=u′,(2π)在上下解反向给定时,利用半序理论和新的比较原理,证明了该周期边值问题最小解和最大解的存在性,解的唯—性,并给出了唯一解的近似迭代序列的误差估计式．更多还原

【Abstract】 In the paper, by the use of the order method and new comparison principles, the author studies the existence of minimal and maximal solutions, the unique solution for the periodic boundary value problems of second order differential equations in Banach spaces, where the problems have upper and lower solutions in the reversed order.更多还原