Topological properties of solution sets for Riemann-Liouville fractional nonlocal delay control systems with noncompact semigroups and applications to approximate controllability

Abstract

This paper investigates the topological properties of the mild solution set for a control system monitored by Riemann-Liouville fractional nonlocal delay evolution equations with noncompact semigroups. We first obtain the Rδ-property of the mild solution set by employing the method of the Hausdorff measure of noncompactness. Then, we apply the obtained result to show that the presented control problem admits a reachable invariant set under nonlinear perturbations. Furthermore, we apply the obtained result to characterize the approximate controllability of the presented control system. Finally, we provide an example to illustrate the application of the abstract results.