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 osym_not_col : forall A B P P',
Reflect P P' A B ->
~ Col A B P -> ~ Col A B P'.