Section T6_2.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.
(* Lemma t2_8 : forall A B C D E : Tpoint, Bet A B C -> Bet D B E -> Cong A B D B -> Cong B C B E -> Cong A E C D. *)

Lemma diff_col_ex : forall A B, exists C, A <> C /\ B <> C /\ Col A B C.