(** This lemma used to be an axiom in previous versions of Tarski's axiom system. It is a been shown to a theorem by Gupta in his Phd 1965. *)
(** This corresponds to l9_6 in Tarski's book. *)

Lemma cop4__col : forall A1 A2 A3 B1 B2 B3 P Q R, ~ Coplanar A1 A2 A3 B1 -> ~ Col B1 B2 B3 ->
Coplanar A1 A2 A3 P -> Coplanar B1 B2 B3 P ->
Coplanar A1 A2 A3 Q -> Coplanar B1 B2 B3 Q ->
Coplanar A1 A2 A3 R -> Coplanar B1 B2 B3 R ->
Col P Q R.