proposition: Lemma ovaluation3 x: \0o <o x -> \0o <o ovaluation x -> limit_ordinal x.
proof: Proof. move => xp vz; move: (ovaluation1 xp) => [y oy ->]; apply:(osum_limit oy). by apply:indecomp_limit2. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)