Require Export GeoCoq.Tarski_dev.Ch11_angles.
Section T12_1.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma par_strict_not_cols : forall A B C D,
Par_strict A B C D -> ~ Col A B C /\ ~ Col B C D /\ ~ Col C D A /\ ~ Col A B D.