End PerpBisect_3.
Section PerpBisect_2D.
Context `{T2D:Tarski_2D}.

(* Specifications: *)
Lemma cong_perp_bisect :
forall P Q A B,
P <> Q -> A <> B ->
Cong A P B P ->
Cong A Q B Q ->
Perp_bisect P Q A B.
Lemma cong_perp_bisect_col : forall A B C D E,
Cong C D C E ->
Perp_bisect A B D E ->
Col A B C.