proposition: Lemma domN_perm_eq D : perm_eq (dom (- D)) (dom D).
proof: Proof. by apply: uniq_perm; rewrite ?uniq_dom //; apply: domN. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order generic_quotient) mathcomp(ssralg ssrnum ssrint)