Pāṇini sūtras

ru is substituted for the m of sam (and thereby a<cb> or aṁ is substituted for a) when the augment s follows, in a samhitâ.

German Für das m von sam wird ru (und davor aṁ oder aṃ für a) substituirt, wenn das Augment s folgt. (5)

1. samaḥसमः

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   sस्	samसम्	samaḥसमः	samसम्	samसम् + plus aḥअः

2. suṭiसुटि

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   sस्	suṭसुट्	suṭiसुटि	suṭसुट्	suṭसुट् + plus iइ

Anuvṛtti

1. ruरु 8·3·1

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   rर्	ruरु	ruरु	ruरु	rर् + plus uउ