Hint Resolve outer_transitivity_between2 between_inner_transitivity between_exchange3 : between.
Section T2_3.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

(* Specifications: *)
Lemma between_exchange2 : forall A B C D, Bet A B D -> Bet B C D -> Bet A C D.
Lemma outer_transitivity_between : forall A B C D, Bet A B C -> Bet B C D -> B<>C -> Bet A B D.
Lemma between_exchange4 : forall A B C D, Bet A B C -> Bet A C D -> Bet A B D.
End T2_3.