End T7_1.
Hint Resolve l7_13 : cong.
Hint Resolve l7_2 l7_3_2 : midpoint.
Ltac Midpoint := auto with midpoint.
Section T7_2.
Context {Tn:Tarski_neutral_dimensionless}.
Context {TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality Tn}.

Lemma l7_17_bis : forall P P' A B, Midpoint A P P' -> Midpoint B P' P -> A=B.