By applying a fixed point theorem, the authors study the existence of positive periodic solutions to a class of differential equations with stated-dependent delay.
运用不动点定理，研究一类具状态依赖时滞的微分方程周期正解的存在性。
By using a well-known fixed point index theorem, we obtain the existence, multiplicity and nonexistence of positive periodic solution(s) to this equation.
利用一个著名的不动点指标定理，获得了该方程周期正解的存在性、多重性和不存在性。
By using the fixed point theorem on cone, this paper studies the existence of positive solutions for first order periodic boundary value problem with impulses.
利用锥上的不动点定理讨论了一阶脉冲微分方程周期边值问题的正解的存在性。
应用推荐