proposition: Lemma perm_eq_fgenum (s : seq (R * K)) (rD : reduced s) : perm_eq (fgenum (\pi_{freeg K / R} (mkPrefreeg s rD))) s.
proof: Proof. exact: perm_eq_fgrepr. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order generic_quotient) mathcomp(ssralg ssrnum ssrint)