Require Export GeoCoq.Elements.OriginalProofs.lemma_sameside2.
Require Export GeoCoq.Elements.OriginalProofs.lemma_10_12.
Require Export GeoCoq.Elements.OriginalProofs.proposition_07.
Section Euclid.
Context `{Ax:euclidean_neutral_ruler_compass}.

(* Specifications: *)
Lemma lemma_erectedperpendicularunique :
forall A B C E,
Per A B C -> Per A B E -> OS C E A B ->
Out B C E.