Fractional integration by parts and Sobolev‐type inequalities for ψ ‐fractional operators

In the present paper, we investigate the Hardy–Littlewood type and the integration by parts result for –Riemann–Liouville fractional integrals. Also, we attack the integration by parts for the –Riemann–Liouville and –Hilfer fractional derivatives. To finish, we investigated Sobolev‐type inequalities involving the –Riemann–Liouville and the –Hilfer fractional derivatives in weighted space.