proposition: Lemma prop_13 : forall A B C D P Q R, A <> B -> B <> C -> B <> D -> Bet C B D -> P <> Q -> Q <> R -> Per P Q R -> SumA C B A A B D C B D /\ SumA P Q R P Q R C B D.
proof: Proof. intros. split. - apply bet__suma; auto. - apply bet_per2__suma; auto. Qed.
imports: GeoCoq.Meta_theory.Continuity.elementary_continuity_props GeoCoq.Tarski_dev.Ch16_coordinates_with_functions