Definition Cong A B C D := (CongH A B C D /\ A <> B /\ C <> D) \/ (A = B /\ C = D).

(* Specifications: *)
Lemma betH_to_bet : forall A B C , BetH A B C -> Bet A B C /\ A <> B /\ B <> C /\ A <> C.
Lemma betH_line : forall A B C, BetH A B C ->
exists l, IncidL A l /\ IncidL B l /\ IncidL C l.