Section Extension.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma extension_reverse_col : forall {Tm: Tarski_neutral_dimensionless}
{Tm2 : Tarski_neutral_dimensionless_with_decidable_point_equality Tm}
(f : @Tpoint Tn -> @Tpoint Tm),
extension f ->
forall A B C, Col (f A) (f B) (f C) -> Col A B C.