proposition: Theorem canword_reduced s : canword s \is reduced.
proof: Proof. Proof using. by apply: (reduced_sprod_code (cocodeP _)); rewrite size_cocode. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(fingroup perm morphism presentation) mathcomp(ssralg poly ssrint) permcomp tools permuted combclass congr