Section T10.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.
Goal forall A B C D, ~ Coplanar D C B A -> ~ Coplanar A B C D.

Lemma l10_7 : forall A B P P' Q Q',
Reflect P' P A B -> Reflect Q' Q A B ->
P'=Q' -> P = Q.