proposition: Lemma OS_CNFp p n: CNFp_ax p n -> natp n -> ordinalp (CNFpv p n).
proof: Proof. move => ax nN. move: (OS_CNFp1 (proj1 ax) nN) => o1. move: (proj2 ax) => [ _ oa /proj1/OS_nat ob]. exact (OS_prod2 (OS_prod2 (OS_oopow oa) ob) o1). Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)