Section TCP_tarski.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma impossible_case_4_1 :
forall A B C D T x y,
A <> D ->
C <> D ->
~ Col A B C ->
Col A C y ->
Bet A D T ->
~ Col B C T ->
Bet B D C ->
Out A B x ->
Bet T y x ->
False.