(* Proof of lem_or_fact                                                    *)
intros; tauto.
Qed.
(* End of proof of lem_or_fact                                             *)

(* Specifications: *)
Lemma lem_or_dist :
forall P0 P1 P2 : Prop, (P0 \/ P2) /\ (P1 \/ P2) -> P0 /\ P1 \/ P2.