End T13.
Section T13_2D.
Context `{T2D:Tarski_2D}.
Context `{TE:@Tarski_euclidean Tn TnEQD}.

Lemma not_par_inter : forall A B A' B' X Y, ~Par A B A' B' -> (exists P, Col P X Y /\ (Col P A B \/ Col P A' B')).