Positivity and uniqueness of solutions for Riemann–Liouville fractional problem of delta types

In this paper, we explore multi positive solutions together with their existence and uniqueness, which is properly defined for delta fractional version of Riemann–Liouville difference operators. Our exploration encompasses two distinct directions. In the first direction, we construct the Green’s function formula for the proposed delta fractional boundary value problems of order δ∈(1,2), and we present some essential properties of this function. The last and main results suggest using the well-known fixed point theorems in a Banach space for testing the existing and uniqueness of multi-positive solutions of such problems.