Section T10_1.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma cong_cop_per2_1 :
forall A B X Y, A <> B -> Per A B X -> Per A B Y ->
Cong B X B Y -> Coplanar A B X Y -> X = Y \/ Midpoint B X Y.