Require Export GeoCoq.Elements.OriginalProofs.lemma_extension.
Require Export GeoCoq.Elements.OriginalProofs.lemma_3_6b.
Section Euclid.
Context `{Ax:euclidean_neutral_ruler_compass}.

(* Specifications: *)
Lemma lemma_outerconnectivity :
forall A B C D,
BetS A B C -> BetS A B D -> ~ BetS B C D -> ~ BetS B D C ->
eq C D.