proposition: Lemma uniq_dom D : uniq (dom D).
proof: Proof. by rewrite /dom; case: repr => /= {}D /andP[]. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order generic_quotient) mathcomp(ssralg ssrnum ssrint)