Multiple positive solutions to third-order three-point singular semipositone boundary value problem

Abstract

By using a specially constructed cone and the fixed point index theory, this paper investigates the existence of multiple positive solutions for the third-order three-point singular semipositone BVP: $\begin{cases} x'''(t)-\ld f(t,x) =0, &t\in(0,1); [.3pc] x(0)=x'(\eta)=x''(1)=0, & \end{cases}$ where ${1/2}<\eta<1$, the non-linear term $f(t,x):(0,1)\times(0,+\i)\to (-\i,+\i)$ is continuous and may be singular at $t=0$, $t=1$, and $x=0$, also may be negative for some values of $t$ and $x$, $\ld$ is a positive parameter.