proposition: Theorem div_firq : forall a b c : R, forall zi : FF, REL a c zi -> REL (a / b) (c / b) zi.
proof: Proof. intros a b c zi (ze, (Hz1, Hz2)). exists ze. split. exact Hz1. rewrite Hz2. unfold Rdiv. ring. Qed.
imports: Reals Gappa_common