Abstract
This paper is devoted to studying the existence and uniqueness of a system of coupled fractional differential equations involving a Riemann-Liouville derivative in the Cartesian product of fractional Sobolev spaces E=Wa+
?
1,1(a,b)xW(a+)
?
2,1(a,b). Our strategy is to endow the space E with a vector-valued norm and apply the Perov fixed point theorem. An example is given to show the usefulness of our main results.