Section par_perp_perp_par_perp_2_par.
Context `{TnEQD:Tarski_neutral_dimensionless_with_decidable_point_equality}.

Lemma par_perp_perp_implies_par_perp_2_par :
perpendicular_transversal_postulate ->
postulate_of_parallelism_of_perpendicular_transversals.