End T4_2.
Hint Resolve not_col_permutation_1 not_col_permutation_2
not_col_permutation_3 not_col_permutation_4 not_col_permutation_5 : col.
Section T4_3.
Context `{Tn:Tarski_neutral_dimensionless}.

Lemma Col_perm :
forall A B C,
Col 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.