(* 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.
Proof with Tarski.
unfold is_midpoint.
intros.
intuition.
eTarski.
Qed.
Proof with Tarski.
unfold is_midpoint.
intros.
intuition.
Qed.
Hint Resolve l7_2 l7_3 l7_3_2 : Midpoint.
Ltac Midpoint := eauto with Midpoint.
Proof with Tarski.
unfold is_midpoint.
intros.
assert (exists E : Point, Bet A P E /\ Cong P E A P)...
DecompExAnd H E.
exists E.
intuition.
Qed.
Hint Resolve symmetric_point_construction : Midpoint.
Proof with Tarski.
unfold is_midpoint.
intros.
intuition.
cases_equality A P.
treat_equalities...
eapply construction_unicity; try apply H0...
esTarski.
Qed.
Proof with Tarski.
unfold is_midpoint.
intros;intuition.
cases_equality A X.
treat_equalities...
eapply (construction_unicity X A X A P Q);Between;sTarski.
Qed.
Proof with sTarski.
intros.
cases_equality P A.
unfold is_midpoint in *.
intuition.
(* *)
treat_equalities...
(* *)
assert (exists X, Bet P' P X /\ Cong P X Q A)...
DecompExAnd H2 X.
assert (exists X', Bet X P' X' /\ Cong P' X' Q A)...
DecompExAnd H2 X'.
assert (exists Y, Bet Q' Q Y /\ Cong Q Y P A)...
DecompExAnd H2 Y.
assert (exists Y', Bet Y Q' Y' /\ Cong Q' Y' P A)...
DecompExAnd H2 Y'.
(* *)
unfold is_midpoint in *;intuition.
(* *)
assert (Cong A X Y A).
apply (l2_11 A P X Y Q A);Between...
(* *)
assert (Cong A Y' X' A).
apply (l2_11 A Q' Y' X' P' A);Between.
eapply cong_transitivity.
apply cong_commutativity.
apply H12.
sTarski.
eapply cong_transitivity;eauto...
(* *)
assert (Cong A Y A Y').
apply (l2_11 A Q Y A Q' Y');Between;eauto...
eapply cong_transitivity;eauto...
(* *)
assert (FSC X A X' Y' Y' A Y X).
unfold FSC;repeat split.
unfold Col;left;Between.
eapply cong_transitivity with (C:=Y) (D:=A)...
4:eapply cong_transitivity with (C:=Y) (D:=A)...
2:eapply cong_transitivity with (C:=Y') (D:=A)...
2:Tarski.
(* *)
eapply (l2_11 X A X' Y' A Y);Between.
eapply cong_transitivity with (C:=Y) (D:=A)...
eapply cong_transitivity with (C:=Y') (D:=A)...
(* *)
assert (X<>A).
unfold not;intro.
treat_equalities...
(* *)
assert (Cong X' Y' Y X).
eapply l4_16.
apply H15.
auto.
(* *)
assert (IFSC Y Q A X Y' Q' A X').
unfold IFSC,FSC in *;intuition;Between...
eapply cong_transitivity with (C:=Y') (D:=A)...
(* *)
assert (Cong Q X Q' X').
eapply l4_2.
apply H18.
(* *)
assert (IFSC X P A Q X' P' A Q').
unfold IFSC,FSC in *;intuition;Between...
(* *)
eapply l4_2.
apply H20.
Qed.
(** Symmetry preserves Bet. *)
Proof with Midpoint.
intros.
eapply l4_6.
apply H2.
unfold Cong_3.
repeat split;eapply l7_13...
Qed.
(** Symmetry preserves Cong. *)
Proof with Midpoint.
intros.
assert (Cong P Q P' Q').
eapply l7_13...
assert (Cong R S R' S').
eapply l7_13...
eapply cong_transitivity with (C:=P) (D:=Q);sTarski.
eapply cong_transitivity with (C:=R) (D:=S);sTarski.
Qed.
(** Symmetry preserves midpoint *)

Lemma symmetry_preserves_midpoint :
forall A B C D E F Z,
is_midpoint Z A D -> is_midpoint Z B E -> is_midpoint Z C F ->
is_midpoint B A C -> is_midpoint E D F.