(* 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 : forall r1 r2, r1 * r2 = 0 -> r1 = 0 \/ r2 = 0.