Pāṇini sūtras

The Participial-affixes do not take iṭ, after those roots, to which another suffix can optionally be added, with or without this augment i

1. yasyaयस्य

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   yय्	yaय	yasyaयस्य	yat [pronoun]	yय् + plus asyaअस्य

2. vibhāṣāविभाषा

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   vव्	vibhāṣविभाष्	vibhāṣāविभाषा	option	vibhāṣविभाष् + plus āआ

Anuvṛtti

1. na+iṭन+इट् 7·2·8

   Part	Lexeme	Sandhi form	Meaning	Stem
   nन्	naन	naन	not	naन
   iइ	iṭइट्	iṭइट्	iṭइट्	iṭइट्

2. niṣṭhāyāmनिष्ठायाम् 7·2·14

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   nन्	niṣṭhनिष्ठ्	niṣṭhāyāmनिष्ठायाम्	niṣṭhāनिष्ठा	niṣṭhनिष्ठ् + plus āyआय्