proposition: Lemma freeg_repr D : [freeg (repr D)] = D.
proof: Proof. apply/eqP/freeg_eqP=> k. by rewrite coeff_Freeg precoeffE /coeff; unlock fglift. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order generic_quotient) mathcomp(ssralg ssrnum ssrint)