Abstract
The aim of this paper is to study multiplicity results for the solutions of a coupled system of fractional differential equations. The problem under consideration is subjected to nonlocal boundary conditions involving Riemann-Liouville integrals and derivatives of fractional order. Necessary and sufficient conditions are established for the existence of at least one and more solutions by using various fixed point theorems of cone type. Moreover sufficient conditions for uniqueness is also discussed by using a concave type operator for the considered problem. Further, the conditions are also provided under which the considered system has no positive solution. The results are demonstrated by providing several examples.