Cathédrale Notre Dame Portail du transept sud, dit portail Saint Etienne, Gables, côté droit Paris 04 Médiathèque de l'architecture et du patrimoine APMH00021092
In geometry, the parallel postulate is the fifth postulate in Euclid's Elements and a distinctive axiom in Euclidean geometry. It states that, in two-dimensional geometry:
The page containing the Parallel Postulate from the 1747 Latin edition of Euclid’s Elements, originally Euclid’s 5th Postulate, here reclassified and presented as Axiom XII by the editor.