(* 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_not_col : forall A B X Y P P', Proj P P' A B X Y -> P <> P' -> ~Col A B P.