Require Export GeoCoq.Elements.OriginalProofs.lemma_NCorder.
Section Euclid.
Context `{Ax:euclidean_neutral}.

(* Specifications: *)
Lemma lemma_oppositesideflip :
forall A B P Q,
TS P A B Q ->
TS P B A Q.
Lemma lemma_samesidesymmetric :
forall A B P Q,
OS P Q A B ->
OS Q P A B /\ OS P Q B A /\ OS Q P B A.