利用Leggett-Williams不动点定理。并赋予f一定的增长条件。证明了二阶微分方程多点边值问题(u″+f(t,u)=0 0≤t≤1 u(0)=0 u(1)-^m-2∑i=1 kiu′(ξ)=0),至少存在3个正解,其中f:[0,1]×[0,∞)→[0,∞)是连续的。0〈ξ〈ξ〈…〈ξm-2〈1.同时给出了该边值问题相应的Green函数。
For a second-order multiple-point boundary value problem system, such as (u″+f(t,u)=0 0≤t≤1 u(0)=0 u(1)-^m-2∑i=1 kiu′(ξ)=0) where f: [0,1]×[0,∞)→[0,∞) is continuous and 0〈ξ〈ξ〈…〈ξm-2〈1, growth conditions are imposed on f, which yields the existence of at least three positive solutions by the Leggett-Williams fixed point theorem. The associat- ed Green function for above problem is also given.