Existence and partial approximate controllability of nonlinear Riemann-Liouville fractional systems of higher order

This article studies the existence and partial approximate controllability of higher order nonlocal semilin-ear fractional differential equations with Riemann-Liouville derivatives avoiding Lipschitz assumptions of nonlinear operator and nonlocal functions. To derive the existence result, we make approximate systems corresponding to the original system. For this, we construct the mild solutions in terms of fractional resolvent. Then, we prove the partial approximate controllability of the nonlinear system by using the obtained existence result. Finally, we give an example to illustrate the established theory.