Satva;tukor asiddhaH

षत्वॱतुकोरसिद्धः ONPANINI 61086

The /Satvam rules and /tuk rules are blind to the changes made by the merge rules.

Example.

Usually, if a word like asicat असिचत् is made of an affix /aT added in front of sicat सिचत् —

a अ + sicat सिचत् → asicat असिचत्

and then we replace that a अ affix by anything that ends in o ओ, then rule /Satvam would work and turn the s स् into S ष्.

Now, if we add together —

kas कस् + asicat असिचत्

Then the merge rule eGaHpadAnt... replaces a अ with o ओ. Ordinarily that would have to trigger /Satvam.

But because of this rule, /Satvam does not trigger, and we get

kosicat कोसिचत् "who sprinkled?"

Now an example with the /tuk rule <15 hrasvasyapit.... It adds /tuk to short vowels before /kyap. But when we add /kyap after /adhi + i इ, the merge rule akassavarN... 15> replaces i इ with I ई, a long. This would ordinarily debar <15 hrasvasyapit....

But because of this rule, <15 hrasvasyapit... triggers anyway and the I ई gets the /tuk as if it were still i इ. So we get —

/adhi + i इ + /kyap
→ adhI अधी + /kyap, by akassavarN... 15>
→ !**adhItya- अधीत्यॱ "which has to be studied", by <15 hrasvasyapit...

61086 Satva;tukor asiddhaH