Require Export GeoCoq.Tarski_dev.Ch05_bet_le.
Ltac eCol := eauto with col.
Section T6_1.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

(** out transitivity. *)
Lemma l6_7 : forall P A B C, Out P A B -> Out P B C -> Out P A C.