“…In light of such applications, a variety of numerical methods [4,5,9,13,17,21,31,32,33,34] have been developed to approximate the solution f in suitable spaces both in the case when the kernel is sufficiently smooth and when it is weakly singular. In order for treating the case of functions presenting algebraic singularities at the endpoints of the interval [0, 1] and/or on the boundary of D, weighted global approximation methods have been recently introduced and studied in [10,14].…”