proposition: Lemma five_segment : forall A A' B B' C C' D D', Cong A B A' B' -> Cong B C B' C' -> Cong A D A' D' -> Cong B D B' D' -> Bet A B C -> Bet A' B' C' -> A <> B -> Cong C D C' D'.
proof: Proof. unfold Bet, Cong;intros. intuition;repeat subst;tauto. Qed.
imports: GeoCoq.Axioms.tarski_axioms