“…Proof. Substituting A = AA 0 into (22) we obtain the operator B 1 in the form (6). Construct the operators B 0 and B by using ( 4) and (5), respectively, where for B we take the elements G, S, Ψ and A from (22) and (23), and for B 0 the elements A 0 , Φ and S 0 , G 0 from (22) and (25), (26).…”