Fractional integral operators on Morrey spaces built on rearrangement-invariant quasi-Banach function spaces

We establish the mapping properties of the fractional integral operators on Morrey spaces built on rearrangement-invariant quasi-Banach function spaces. As applications of our main result, we have the mapping properties of the Riemann-Liouville fractional integral and the Weyl fractional integral on Morrey spaces built on rearrangement-invariant quasi-Banach function spaces. We also give an application of our main result on Orlicz-Morrey spaces. Copyright © 2023 The Author(s), under exclusive licence to Springer Nature Switzerland AG.