proposition: Lemma T1transfinite_induction P: (forall x, T1nf x -> (forall y, T1nf y -> y < x -> P y) -> P x) -> forall a, T1nf a -> P a.
proof: Proof. move => H; exact: (P_well_founded_induction_type nf_Wf' H). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(fintype bigop)