(* Gabriel Braun March 2013 *)
Require Export GeoCoq.Tarski_dev.Annexes.vectors.
Section Projections.
Context `{T2D:Tarski_2D}.
Context `{TE:@Tarski_euclidean Tn TnEQD}.

Lemma project_par : forall A B X Y P Q P' Q', Proj P P' A B X Y -> Proj Q Q' A B X Y -> Par P Q X Y -> P' = Q'.