关键词: 三阶常微分方程, 周期边值, Green函数, 正解

Abstract: By using the fixed point theorem on expansion and  compression of cones, we study the existence of positive solutions for a class of periodic boundary value problems of third-order ordinary differential equations. The  results show that there exists  at least one positive solution to the above problem when the nonlinear term f satisfies appropriate conditions.

Key words: third-order differential equation, periodic boundary value, Green function, positive solution