Require Export GeoCoq.Tarski_dev.Ch05_bet_le.
Ltac eCol := eauto with col.
Section T6_1.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma col_transitivity_1 : forall P Q A B,
P<>Q -> Col P Q A -> Col P Q B -> Col P A B.