deriv SD cv (326) ashtadhyayi.com hei.de L 326 ETT STT a 7.2.84 ALPH OLDHOMEPAGE NEWHOMEPAGE

aSTana:: A vibhaktau

अष्टन‌ आ विभक्तौ ONPANINI 72084

Optionally replace aSTan- अष्टन् with A आ before (consonant) /sup.

aSTan अष्टन् + /sup' → aSTasu अष्टसु by nalopaHprAt... → aSTAsu अष्टासु by this rule.

aSTAbhyaH अष्टाभ्यः

aSTAnAm अष्टानाम्

ITA —

aSTan अष्टन् + /sup' → aSTasu अष्टसु losing n न् when /pada

How do we know that this rule is optional, even though it has no /vA?

Because if it were compulsory, rule aSTAbhya::auz would have been aSTabhya::auz अष्टभ्य‌औश्.