(* For consistency with Rplus_opp_r and Rplus_opp_l. *)
Definition Rmult_inv_r := Rinv_r.Definition Rmult_inv_l := Rinv_l.

Lemma Rmult_integral_contrapositive : forall r1 r2, r1 <> 0 /\ r2 <> 0 -> r1 * r2 <> 0.