Notice of RetractionThree positive solutions of nonlinear boundary value problems with sign changing nonlinearity

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

The presenting author of this paper has the option to appeal this decision by contacting TPII@ieee.org.

In this paper, we study the existence of positive solutions for a class nonlinear boundary value problem { (Φ_p(u´))´+ a(t)f(u) = 0, 0 <; t <; 1, u´(0) =u(1) = 0, Φ_p(s)= |s|^p-2s, p>1. We obtain the existence of three positive solutions by using Leggett-Williams fixed-point theorem in a cone. Especially, the nonlinear terms f is allowed to change sign. The conclusions in this paper essentially extend and improve the known results.