intros.
induction(eq_dec_points B B').
subst B'.
assert(Col A B C').
apply (col3 P Q); try auto.
assert(Col P A B).
eapply (col_transitivity_1 _ Q); try auto.
assert(Col Q A B).
eapply (col_transitivity_1 _ P).
auto.
Col.
Col.
induction(eq_dec_points A B).
subst B.
apply between_trivial2.
assert(Col P Q C).
eapply col3.
apply H12.
Col.
Col.
apply bet_col.
assumption.
assert(Col P C' C).
eapply col_transitivity_1.
apply H.
assumption.
assumption.
assert(P=C' \/ C=C').
eapply l8_9.
apply l8_2.
assumption.
assumption.
induction H15.
subst C'.
tauto.
subst C'.
assumption.
(* A=A' et B<>B' *)
induction(eq_dec_points A C).
subst C.
apply between_identity in H0.
subst B.
assert(B'=C').
eapply per_id.
4:apply H2.
assumption.
auto.
auto.
assumption.
eapply (col_transitivity_1 _ Q); auto.
subst C'.
apply between_trivial.
assert(C <> C').
intro.
subst C'.
assert(Col P A C).
eapply (col_transitivity_1 _ Q); try auto.
assert(Col A C B').
eapply col3.
apply H.
assumption.
assumption.
assumption.
assert(Col P B' B).
eapply col3.
3:apply H12.
assumption.
Col.
apply col_permutation_5.
apply bet_col.
assumption.
assert(B=B' \/ P=B').
eapply l8_9.
assumption.
Col.
induction H14.
subst B'.
tauto.
auto.
induction (eq_dec_points A B').
subst B'.
apply between_trivial2.
assert(A <> B).
intro.
subst B.
apply per_not_col in H2.
apply H2.
ColR.
assumption.
auto.
induction(col_dec C B B').
assert(C=B).
eapply (l6_21 B B').
assert(Per B B' A).
eapply (per_col _ _ P).
auto.
assumption.
ColR.
apply per_not_col in H15.
apply H15.
auto.
auto.
apply H13.
Col.
Col.
apply bet_col.
apply H0.
Col.
subst C.
assert(B'=C').
eapply per_id.
4:apply H2.
auto.
auto.
auto.
auto.
ColR.
subst C'.
apply between_trivial.
assert(Perp B' B' B' P \/ Perp B B' B' P).
eapply perp_in_perp_bis.
apply per_perp_in.
auto.
auto.
assumption.
induction H15.
apply perp_not_eq_1 in H15.
tauto.
assert(Perp C' C' C' P \/ Perp C C' C' P).
eapply perp_in_perp_bis.
apply per_perp_in.
auto.
auto.
assumption.
induction H16.
apply perp_not_eq_1 in H16.
tauto.
assert(Par B B' C C').
eapply l12_9_2D.
apply H15.
apply perp_sym.
apply perp_left_comm.
eapply perp_col.
auto.
apply perp_left_comm.
apply perp_sym.
apply H16.
eapply (col_transitivity_1 _ Q);
auto.
unfold Par in H17.
assert(Par_strict B B' C C').
induction H17.
assumption.
spliter.
apply False_ind.
apply H14.
ColR.
clear H17.
assert(OS B B' C C').
eapply l12_6.
assumption.
assert(Per B B' A).
eapply (per_col _ _ P); try auto.
ColR.
induction(eq_dec_points A C').
subst C'.
assert(TS B B' A C).
unfold TS.
repeat split; try auto.
apply per_not_col in H19.
intro.
apply H19.
Col.
auto.
auto.
exists B.
split.
Col.
assumption.
apply l9_2 in H20.
apply l9_9 in H20.
contradiction.
assert(TS B B' A C).
unfold TS.
repeat split; try auto.
apply per_not_col in H19.
intro.
apply H19.
Col.
auto.
auto.
exists B.
split.
Col.
assumption.
assert(TS B B' C' A).
eapply l9_8_2.
apply l9_2.
apply H21.
assumption.
unfold TS in H22.
spliter.
ex_and H24 T.
assert(T = B').
eapply l6_21.
apply not_col_permutation_1.
apply H23.
4: apply bet_col in H25.
4: apply col_permutation_2.
4: apply H25.
auto.
Col.
Col.
ColR.
subst T.
Between.
Qed.

Lemma perp_not_eq_3 : forall A B C, Perp A B B C -> A <> C.
intros.