proposition: Lemma reduced_rconsK u i : rcons u i \is reduced -> u \is reduced.
proof: Proof. Proof using. by rewrite -cats1; exact: reduced_catl. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(fingroup perm morphism presentation) mathcomp(ssralg poly ssrint) permcomp tools permuted combclass congr