Section Extension.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma col2_diff_inj_line__diff : forall {Tm: Tarski_neutral_dimensionless}
(f : @Tpoint Tn -> @Tpoint Tm) P Q, inj_line f P Q ->
forall A B, Col P Q A -> Col P Q B -> A <> B -> f A <> f B.