Pāṇini sūtras

After the verb tapa ‘to shine,’ when used intransitively, and preceded by ut or vi the Atmanepada affix is employed.

German An tap mit ud und vi in intransitiver Bedeutung. (27)

1. ud+vibhyāmउद्+विभ्याम्

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   uउ	udउद्	udउद्	udउद्	udउद्
   vव्	viवि	vibhyāmविभ्याम्	viवि	vव् + plus ibhyāइभ्या

2. tapaḥतपः

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   tत्	tapतप्	tapaḥतपः	tapतप्	tapतप् + plus aḥअः

Anuvṛtti

1. ātmanepadamआत्मनेपदम् 1·3·12

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   āआ	ātmanepadaआत्मनेपद	ātmanepadamआत्मनेपदम्	medium voice	ātmanepadआत्मनेपद् + plus amअम्

2. akarmakātअकर्मकात् 1·3·26

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   aअ	akarmakaअकर्मक	akarmakātअकर्मकात्	intransitive	akarmakअकर्मक् + plus ātआत्