proposition: Lemma Rmorph_rat a : phi (ratR R a) == ratR S a.
proof: Proof. by rewrite /ratR; case: ifP; rewrite ?phiM ?Rmorph_inv !Rmorph_int. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq order) mathcomp(ssralg ssrnum ssrint rat) Coq(Morphisms Setoid) fourcolor(real realsyntax realprop)