本文研究一类二阶脉冲微分方程: {″(t)+f(t,x(t),x'(t))=0,t≠ti △x(ti)=Ii(x(ti),x'(ti)),i=1,2,3,…,k △x'(ti)=Ji(x(ti),x'(t)), x(0)=0=x(1)-αx(η),的正解存在性.其中,0〈η〈1,0〈α〈1, f:[0,1]×(0,∞)×R→[0,∞),Ii:[0,∞)×R→R,Ji:[0,∞)×R→R,(i=1,2,…,k)均为连续函数.本文所用方法是文献[5]推广的Krasnoselskii不动点定理,此定理为解决依赖于一阶导数的边值问题提供了理论依据.基于此定理,获得了问题正解存在性定理.特别地,我们获得此类问题的Green函数,使问题的解决更直观和简单.
We study positive solutions for second order three-point boundary value problem: {″(t)+f(t,x(t),x'(t))=0,t≠ti △x(ti)=Ii(x(ti),x'(ti)),i=1,2,3,…,k △x'(ti)=Ji(x(ti),x'(t)), x(0)=0=x(1)-αx(η), where 0〈η〈1,0〈α〈1,and f:[0,1]×(0,∞)×R→[0,∞),Ii:[0,∞)×R→R,Ji:[0,∞)×R→R,(i=1,2,…,k)are continuous. Based on a new extension of Krasnoselskii fixed-point theorem (which was established by Guo Yan-ping and GE Wei-gao, the existence of positive solutions for the boundary value problems is obtained. In particular, we obtain the Green function of the problem, which makes the problem simpler.