proposition: Lemma pmulRI x y z : x > 0 -> x * y == x * z -> y == z.
proof: Proof. by move=> x_gt0 Dxy; rewrite -(pmulKR y x_gt0) Dxy pmulKR. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div order) mathcomp(ssralg ssrnum ssrint rat intdiv) Coq(Morphisms Setoid) fourcolor(real realsyntax)