proposition: Lemma cocodeP s : cocode s \is a code.
proof: Proof. Proof using. by have:= cocode2P s => /= [] []. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(fingroup perm morphism presentation) mathcomp(ssralg poly ssrint) permcomp tools permuted combclass congr