摘要：In this work, we deal with two-point Riemann–Liouville fractional boundary value problems. Firstly, we establish a new comparison principle. Then, we show the existence of extremal solutions for the two-point Riemann–Liouville fractional boundary value problems, using the method of upper and lower solutions. The performance of the approach is tested through a numerical example.
关键词：Riemann–Liouville derivative ; Boundary value problem ; Upper and lower solutions ; Maximal and minimal solutions
