proposition: Lemma Dyck_rp_auxK l: starts_withFT l -> Dyck_lp_aux (Dyck_rp_aux l) = l.
proof: Proof. by rewrite /Dyck_rp_aux/Dyck_lp_aux DP_raiseK starts_withFT_prop => /eqP. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype) mathcomp(ssrnat seq path div) mathcomp(fintype tuple finfun bigop finset binomial)