Pāṇini sūtras

iyaṅ and uvaṅ are substituted for the i and u of a reduplicate, before a non-homogenous vowel.

German Auh für das i und u einer Reduplication vor einem nicht homogenen Vocale. (78)

1. abhyāsasyaअभ्यासस्य

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   aअ	abhyāsaअभ्यास	abhyāsasyaअभ्यासस्य	reduplication	abhyāsअभ्यास् + plus asyaअस्य

2. a+savarṇeअ+सवर्णे

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   aअ	aअ	aअ	not	aअ
   sस्	savarṇaसवर्ण	savarṇeसवर्णे	homophonous	savarṇसवर्ण् + plus eए

Anuvṛtti

1. bhātभात् 6·4·22

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   bब्	bhaभ	bhātभात्	bhaभ	bhभ् + plus ātआत्

2. iyaṅ+uvaṅauइयङ्+उवङौ 6·4·77

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   iइ	iyaṅइयङ्	iyaṅइयङ्	iyaṅइयङ्	iyaṅइयङ्
   uउ	uvaṅउवङ्	uvaṅauउवङौ	uvaṅउवङ्	uvaṅउवङ् + plus auऔ