Copyright © 2009 Ravi P. Agarwal et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
We establish sufficient conditions for the existence of mild solutions
for some densely defined semilinear functional differential equations and inclusions involving the
Riemann-Liouville fractional derivative. Our approach is based on the -semigroups theory combined
with some suitable fixed point theorems.