(* Gabriel Braun April 2013 *)
Require Export GeoCoq.Tarski_dev.Ch13_4_cos.
Require Export GeoCoq.Tarski_dev.Annexes.project.
Section Pappus_Pascal.
Context `{T2D:Tarski_2D}.
Context `{TE:@Tarski_euclidean Tn TnEQD}.

Lemma l13_10_aux1 : forall O A B P Q la lb lp lq,
Col O A B -> Col O P Q -> Perp O P P A -> Perp O Q Q B ->
Q_Cong la -> Q_Cong lb -> Q_Cong lp -> Q_Cong lq -> la O A -> lb O B -> lp O P -> lq O Q ->
exists a, Q_CongA_Acute a /\ Lcos lp la a /\ Lcos lq lb a.