“…Nevertheless, it is showed rigorously that this closure scheme is convergent to (6) if α < 0 and to the inconsistent solution (8) if α > 0 [20]. A more sophisticated closure scheme consists in applying to the nth equation the relation [19] y 2n+2 (α,β,σ ) = γ y 2n (α,β,σ ), γ > 0, (11) but it gives the same result [20].…”