proposition: Lemma eq_incident : forall A l m, l =l= m -> (IncidentL A l <-> IncidentL A m).
proof: Proof. intros. split;intros; unfold EqL in *; assert (T:= H A); intuition. 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