Require Export E1_Incidence.
Section ORDERING.
(* B1 : If B is between A and C, then A, B, C are distinct points on a line, and also B is between C and A. *)

(* Specifications: *)
Lemma B1a : forall A B C,
Between A B C -> A <> B.
Lemma B1b : forall A B C,
Between A B C -> B <> C.
Lemma B1c : forall A B C,
Between A B C -> C <> A.
Lemma B1d : forall A B C,
Between A B C -> Collinear A B C.
Lemma B1e : forall A B C,
Between A B C -> Between C B A.