The fourth out of the fourteen Pūrvas (canonical works of earlier lore);
it contains the exposition of existence and nonexistence.
cauttheṃ atthiṇatthippavādaṃ, jaṃ loye jahā atthi jahā vā ṇatthi, ahavā sitavādābhippādato tadevāsti nāstityevaṃ pravadati.
(Nandī 104 Cū p. 75)