proposition: Lemma succ_psiCE (z := [zero,zero, T3bad]): (omega < z) && (z < (psi_succ omega)) && ~~(T3nf z).
proof: Proof. done. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(fintype bigop)