Existence and Uniqueness of Positive Solution for a Nonlinear Multi-Order Fractional Differential Equations

Abstract

This paper is concerned with a class of nonlinear multi-order fractional differential equation. By constructing the upper and lower control functions of the nonlinear term without any monotone requirement and applying the method of upper and lower solutions and Schauder fixed point theorem, the existence and uniqueness of positive solution for the equation are investigated. Moreover, some properties concerning the maximal, minimal, and continuation of solutions are obtained.