Require Export GeoCoq.Meta_theory.Decidability.equivalence_between_decidability_properties_of_basic_relations.
Section T5.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma l5_1 : forall A B C D,
A<>B -> Bet A B C -> Bet A B D -> Bet A C D \/ Bet A D C.