श्र्य्-उकः किति

Karika

वाच्य ऊर्णोर्नुवद्भावो यङ्प्रसिद्धिः प्रयोजनम् ।
आमश्च प्रतिषेधार्थमेकाचश्चेडुपग्रहात् ॥

As श्रित्वा, श्रितः, श्रितवान् ॥ So also with roots ending in उक् vowels : as युत्वा, युतः, युतवान्; लूत्वा, लूनः, लूनवान्; वृत्वा, वृतः, वृतवान्; तीर्त्वा, तीर्णः, तीर्णवान् ॥

Why 'श्रि and उक् ending roots only'? Observe विदितः ॥ Why having an indicatory क्? Observe श्रयितृ, श्रयितुम्, श्रयितव्यम् ॥ Some read two क's in the sutra and would apply it to the indicatory ग् also, as भूष्णु 3.2.139.

This rule applies to those roots, which have not been enumerated above. In the case of यु the Nishtha will not take इट् even by 7.2.49 read with 7.2.15.

When two क are read in the sutra, one standing for ग्; there arises a little difficulty of combination. Thus ग् coming after the visarga of उकः would require that the visarga be changed to उ by 6.1.114. If ग् be changed to क् 8.4.55 then also, the visarga required to be changed into upadhmaniya by 8.3.37. If the change of ग् into क् 8.4.55 be considered asiddha (VIII. 2. 1.), then also the visarga must be changed to उ 6.1.114, and the sutra should be श्र्युकोकिति ॥ This, however, is not done as an anomaly allowable in sutra construction. According to Kasika, this difficulty would not at all arise, if in the sutra ग्लाजिस्थश्चक्स्नु 3.2.139, the स्था + आ be taken as compounded into स्था; so that that rule would apply to that स्था which ends in आ, and not to that स्था whose final is changed to ई; so that the form स्थास्नुः is evolved without anomaly: and the affix will be कित् (क्स्नु) and not गित् (ग्स्नु). The affix being कित्, the above sandhi difficulty will not arise at all.

The word उपदेश is understood here also, so that the rule will apply to roots which end in उक् vowel, in their original states and not to the transformed base before the affix. Thus तॄ is a उक्-ending root, which is transformed to तीर् before the Nishtha त ॥ The rule will apply to it, as तीर्णः ॥ If you object saying, that तॄ ends in long ॠ and its Desiderative optionally takes इट् by 7.2.41, and therefore, its Nishtha will always take no इट् by 7.2.15. we reply, that the option taught in 7.2.41 applies to roots ending in long ॠ; but when the root vowel is changed to ई, it is no longer a ॠ-ending root. If you say, the rule of sthanivad bhava will apply: we say, that that rule is not applicable to अल् विधि, and this is an अल्विधि ॥ Therefore, the word उपदेश should be read into this sutra. If this be so, the rule ought to apply to जागृ, and we could not get the forms जागरितः and जागरितवान् ॥ To explain this we should also read the anuvritti of एकाच् into this sutra. The root ऊर्णु, however is an exception and is governed by this rule, in spite of its consisting of more than one vowel. Thus प्रोर्णुतः and प्रोर्णुतवान् ॥

Karika:- ऊर्णु is treated as if it was नु, when the affix यङ् is to be applied, आम् is to be prohibited, or इट् is to be debarred.,