proposition: Lemma perp_bisect_existence : forall A B, A <> B -> exists P, exists Q, Perp_bisect P Q A B.
proof: Proof. intros A B HDiff. destruct (perp_bisect_cop2_existence A B A HDiff) as [P [Q []]]. exists P; exists Q; assumption. Qed.
imports: GeoCoq.Tarski_dev.Ch10_line_reflexivity_2