proposition: Fact norm_ratN x : normq (- x) = normq x.
proof: Proof. by rewrite !normqE numqN denqN normrN. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order ssralg countalg div ssrnum) mathcomp(ssrint prime archimedean)