“…Eq. (26) has a unique solution (27) where the operator is an integral operator which can be written in terms of powers of the operator 32, pp.378 , , , , , , , , , 3 2 1 0 3 2 1 0 2 3 2 1 0 3 (28) Such that the powers of are also integrals operators. , , ; , , , , , , , 1 1 2 2 3 3 0 3 2 1 0 3…”