Pāṇini sūtras

For the ā being a portion of a sarvadhâtuka ‘Personal ending which is ṅit (i.e. āte, āthe, ātām and āthām), coming after a Verbal stem ending in short a, there is substituted iy

1. ā+taḥआ+तः

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   āआ	āआ	āआ	ākāraआकार	āआ
   tत्	tत्	taḥतः	TT	tत् + plus aḥअः

2. ṅ+itaḥङ्+इतः

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   ṅङ्	ṅङ्	ṅङ्	ṅakāraङकार	ṅङ्
   iइ	itइत्	itaḥइतः	itइत्	itइत् + plus aḥअः

Anuvṛtti

1. sārvadhātukeसार्वधातुके 7·2·76

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   sस्	sārvadhātuसार्वधातु	sārvadhātukeसार्वधातुके	sārvadhātukaसार्वधातुक	sārvadhātukसार्वधातुक् + plus eए

2. yā+iyaḥया+इयः 7·2·80

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   iइ	iyइय्	iyaḥइयः	iyइय्	iyइय् + plus aḥअः