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

Lemma not_par_strict_inter_exists :
forall A1 B1 A2 B2,
~Par_strict A1 B1 A2 B2 ->
exists X, Col X A1 B1 /\ Col X A2 B2.