 Let "F" = (span{"en"})⊥, where {"en"} is the finite or infinite sequence constructed by the inductive process; by self-adjointness, "F" is invariant under "T".Let "S" denote the restriction of "T" to "F".If the process was stopped after finitely many steps, with a last vector "e""m"−1, then "F"= "Hm" and "S" = "Tm" = 0 by construction.