proposition: Lemma NColB_NDiffCol : forall A B C, ~ ColB A B C -> ~ Col A B C.
proof: Proof. intros A B C HNCB. intro HNC. apply HNCB. apply Diff_Col_ColB. assumption. Qed.
imports: GeoCoq.Axioms.beeson_s_axioms GeoCoq.Tarski_dev.Ch08_orthogonality