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

Lemma col2__eq : forall A B X Y,
Col A X Y -> Col B X Y -> ~ Col A X B ->
X = Y.