proposition: Lemma axiom_conga_comm : forall A B C, ~ Col_H A B C -> CongA A B C C B A.
proof: Proof. intros. rewrite <- cols_coincide in H. assert_diffs. apply conga_pseudo_refl;auto. Qed.
imports: Morphisms GeoCoq.Axioms.hilbert_axioms GeoCoq.Axioms.parallel_postulates GeoCoq.Meta_theory.Parallel_postulates.tarski_playfair GeoCoq.Meta_theory.Parallel_postulates.SPP_ID GeoCoq.Meta_theory.Dimension_axioms.upper_dim_3 GeoCoq.Meta_theory.Parallel_postulates.parallel_postulates GeoCoq.Utils.triples