Section T6_1.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.
(** out reflexivity. l6_5 *)
(** out symmetry. *)
(** out transitivity. *)

Lemma col_transitivity_1 : forall P Q A B,
P<>Q -> Col P Q A -> Col P Q B -> Col P A B.