proposition: Lemma path_braidred_catl p u w : path braidred u p -> path braidred (u ++ w) [seq v ++ w | v <- p].
proof: Proof. Proof using. elim: p u => [//= | p0 p IHp] u /= /andP[Hbr /IHp ->]. by rewrite braidred_catl. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(fingroup perm morphism presentation) mathcomp(ssralg poly ssrint) permcomp tools permuted combclass congr