Results on Extremal Solutions for a Class of Boundary Value Problem of Nonlinear Fractional Order Differential Equations

This paper investigates a class of boundary value problems involving Caputo fractional derivatives of order ν∈(2,3]. We begin by establishing two novel comparison principles. Subsequently, by employing the monotone iterative technique coupled with upper and lower solutions, we demonstrate the existence of extremal solutions for the corresponding fractional differential equations. Finally, an illustrative example is provided to validate our main findings.