Definition: not nitya or obligatory optional; said of a rule or paribhāṣā whose application is voluntary). Regarding the case and con= jugational affixes it can be said that those affixes can, in a way: be looked upon as nitya or obligatory, as they have to be affixed to a crude nominal base or a root; there being a dictum that no crude base without an affix can be used as also, no affix alone without a base can be used. On the other hand, the taddhita and kṛt affixes as also compounds are voluntary as, instead of them an independent word or a phrase can be used to convey the sense. For a list of such nitya affixes see M. Bh. on V. 4.7; (2) the word अनित्य is also used in the sense of not-nitya, the word नित्य being taken to mean कृताकृतप्रसङ्गि occurring before as well as after another rule has been applied, the latter being looked upon as अनित्य which does not do so. This 'nityatva' has got a number of exceptions and limitations which are mentioned in Paribhāṣās 43-49 in the Paribhāṣenduśekhara.