Section T4_4.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma NCol_cases :
forall A B C,
~ Col A B C \/ ~ Col A C B \/ ~ Col B A C \/
~ Col B C A \/ ~ Col C A B \/ ~ Col C B A ->
~ Col A B C.