Pāṇini sūtras

After a root which possesses a short a as its root-vowel in the original enunciation (the Dhâtupâṭha), and after which the Peri-Fut. tām is always devoid of the augment iṭ, thal the Personal ending of the Perfect, like tās, does not get the augment iṭ

1. upadeśeउपदेशे

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   uउ	upadeśaउपदेश	upadeśeउपदेशे	linguistics	upadeśउपदेश् + plus eए

2. atvataḥअत्वतः

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   aअ	atvatअत्वत्	atvataḥअत्वतः	atvatअत्वत्	atvअत्व् + plus ataḥअतः

Anuvṛtti

1. va+l+ādeḥव+ल्+आदेः 7·2·35

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   vव्	vaव	vaव	vakāraवकार	vव् + plus aअ
   lल्	lल्	lल्	LL	lल्
   āआ	ādiआदि	ādeḥआदेः	first syllable	ādआद् + plus eḥएः

2. naन 7·2·59

   Part	Lexeme	Sandhi form	Meaning	Stem
   nन्	naन	naन	not	naन

3. nityamनित्यम् 7·2·61

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   nन्	nityaनित्य	nityamनित्यम्	continuous	nityनित्य् + plus amअम्