proposition: Lemma ratMult_ratDistance_factor_l : forall r1 r2 r3, ratDistance (r3 * r1) (r3 * r2) == r3 * (ratDistance r1 r2).
proof: Proof. intuition. repeat rewrite (ratMult_comm r3). eapply ratMult_ratDistance_factor_r. Qed.
imports: micromega.Lia List FCF.StdNat Arith Lia Setoid RelationClasses Coq.Classes.Morphisms