proposition: Lemma pi_fglift : {mono \pi_{freeg K / R} : D / lift D >-> fglift D}.
proof: Proof. by case=> [s reds]; unlock fglift; exact/prelift_perm_eq/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)