Positive solutions of a nonlinear second-order n-point boundary value problem

In this paper, we study the existence of at least one or two positive solutions to the n-point boundary value problemu″(t)+a(t)f(u)=0,t∈(0,1),u′(0)=∑i=1n-2biu′(ξi),u(1)=∑i=1kaiu(ξi)-∑i=k+1saiu(ξi)-∑i=s+1n-2aiu′(ξi),where 1 ⩽ k ⩽ s ⩽ n − 2, ai, bi ∈ [0, ∞) with 0<∑i=1kai-∑i=k+1sai<1,∑i=1n-2bi<1,0<ξ1<ξ2<⋯<ξn-2<1. The Krasnoselskii's fixed-point theorem is used.