End T11_1.
Section T11_2.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma l11_16 : forall A B C A' B' C',
Per A B C    -> A <> B  -> C <> B ->
Per A' B' C' -> A'<> B' -> C'<> B'->
CongA A B C A' B' C'.