A multiplicity result for periodic solutions of higher order ordinary differential equations via the method of upper and lower solutions

Abstract

We prove a multiplicity result of Ambrosetti–Prodi type problems of higher order. Proofs are based on upper and lower solutions method for higher order periodic boundary value problems and coincidence degree arguments.

Keywords

• Existence
• Multiplicity
• Periodic solution
• Higher order ordinary differential equation
• Ambrosett–Prodi type problem
• Upper solution
• Lower solution
• <it>A priori</it> estimate
• Coincidence degree