proposition: Lemma ratRN a : (- a)%R == - a.
proof: Proof. by rewrite !ratRE numqN denqN intRN mulNR. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div order) mathcomp(ssralg ssrnum ssrint rat intdiv) Coq(Morphisms Setoid) fourcolor(real realsyntax)