Triple positive solutions for a class of boundary value problem of second-order functional differential equations

We obtain sufficient conditions for the existence of at least three positive solutions for the functional differential equation x″(t)+q(t)f(t,x(t),x′(t-1))=0 subject to some boundary conditions. This is an application of a new fixed-point theorem introduced by Avery and Peterson (Ann. Differential Equations 8 (1992) 261-268).