proposition: Lemma cop_npar__inter_exists : forall A1 B1 A2 B2, Coplanar A1 B1 A2 B2 -> ~ Par A1 B1 A2 B2 -> exists X, Col X A1 B1 /\ Col X A2 B2.
proof: Proof. intros. apply cop_npars__inter_exists. assumption. intro. apply H0. left. assumption. Qed.
imports: GeoCoq.Meta_theory.Parallel_postulates.parallel_postulates GeoCoq.Meta_theory.Parallel_postulates.par_trans_NID