Section Beeson_1.
(** Another proof of l2_11 without eq_dec_points but using Cong stability inspired by Micheal Beeson. #<a href="http://www.michaelbeeson.com/research/papers/AxiomatizingConstructiveGeometry.pdf"></a> # *)
Context `{Tn:Tarski_neutral_dimensionless}.
Variable Cong_stability : forall A B C D, ~ ~ Cong A B C D -> Cong A B C D.

Lemma cong_dec_eq_dec_b :
(forall A B:Tpoint, ~ A <> B -> A = B).