(* Julien Narboux *)
(* Formalization of *)
(* Tarski's axiomatic *)
Require Export Ch06_out_lines.
Unset Regular Subst Tactic.
Definition is_midpoint := fun M A B => Bet A M B /\ Cong A M M B.
Proof with Tarski.
unfold is_midpoint.
intros.
intuition.
Qed.

Lemma l7_3 : forall M A, is_midpoint M A A -> M=A.