deriv SD cv (690) ashtadhyayi.com hei.de L 690 ETT STT a 7.4.61 ALPH OLDHOMEPAGE NEWHOMEPAGE

zar-pUrvAH khayaH

शर्पूर्वाः खयः ONPANINI 74061

But only a stop stays, if after /zar.

Exception to < halAdizzeSaH.

sthA स्था + sthA स्था + /san
thA था + sthA स्था + /san by this rule
thi थि + sthA स्था + /san by sanyataH 18>
ti ति + sthA स्था + /san by abhyAsecarca
ti ति + SthA ष्था + /san with /Satvam
ti ति + SThA ष्ठा + /san by STunASTuH
→ !**tiSThAsa- तिष्ठासॱ

stu स्तु + stu स्तु
→ tuStu तुष्तु with /Satvam
→ tuSTu तुष्टु by STunASTuH
→ !**tuSTu- तुष्टुॱ

Why do we say "if after /zar"? Coulson just says "if after s स्".

There are no roots starting with S ष् (see Sa-roots). So Coulson is right if we ignore the root zcu श्चु —

zcu श्चु "ooze, drip" + /liT
→ !**cuzcu- चुश्चुॱ + /liT

and there is little need of mentioning it because the MMW tells you that it reduplicates to **cuzcu- चुश्चुॱ.