Section Tarski_is_a_Coinc_theory_for_col.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.
Definition diff : arity Tpoint 2 := fun A B : Tpoint => A <> B.

Lemma diff_perm_1 : forall A B, app_1_n diff A B -> app_n_1 diff B A.