deriv SD cv (283) ashtadhyayi.com hei.de L 283 ETT STT a 6.1.108 ALPH OLDHOMEPAGE NEWHOMEPAGE

samprasAraNAc ca

संप्रसारणाच्च ONPANINI 61108

A /samprasAraNa vowel and the next vowel merge into the former.

See igyaNassampr... for examples.

Given that this rule invariably triggers when /yaN letters are replaced with /samprasAraNa vowels, why didn't /pANini include the deletion of the second vowel directly into the wording of sUtra igyaNassampr...?

Because he wanted this to be a merge, subject to antAdivacca.

And why is that important?

I'll leave that as an exercise for the diligent student.