Pāṇini sūtras

The affix ṭa comes after the verb sṛ ‘to move’ when the words in composition with it, are puraḥ, agrataḥ and agre, all meaning ‘in front of or before’.

1. puras+agratas+agreṣuपुरस्+अग्रतस्+अग्रेषु

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   pप्	purasपुरस्	purasपुरस्	puras [word]	purasपुरस्
   aअ	agratasअग्रतस्	agratasअग्रतस्	agratas [word]	agratasअग्रतस्
   aअ	agraअग्र	agreṣuअग्रेषु	agra [word]	agrअग्र् + plus eṣuएषु

2. sarteḥसर्तेः

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   sस्	sartiसर्ति	sarteḥसर्तेः	sṛसृ	sartसर्त् + plus eḥएः

Anuvṛtti

1. ṭaḥटः 3·2·16

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   ṭट्	ṭaट	ṭaḥटः	ṭaट	ṭट् + plus aḥअः