Require Export GeoCoq.Tarski_dev.Ch10_line_reflexivity.
Section T10_1.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma two_sides_cases : forall O P A B,
~ Col O A B -> OS O P A B -> TS O A P B \/ TS O B P A.