A long vowel is substituted for the a of the reduplicate in the Intensive (with expressed or elided yaṅ) when the reduplicate receives no augment having an indicatory k ,
The reduplicate receives augments like मीक्, मुक् by the following sutras. Thus पापच्यते, and पापचीति, यायज्यते and यायजीति ॥ Why do we say \when it gets no augment\? Observe यंयम्यते, यंयमीति, रंरम्यते, रंरमीति ॥
Objection:- When the न् augment is added, the reduplicate will end in a consonant, and as it does not end in a vowel, there will be no occasion for lengthening; hence the employment of the term अकितः is useless.
Answer:- The employment of this term by the Acharya indicates the existence of the following maxim : अभ्यासविकारेष्वपवादानोत्सर्गान् विधीन् बाधन्ते \so far as changes of a reduplicative syllable are concerned, rules which teach those changes do not supersede one another\. What is the necessity of this indication (jnapaka)? Observe डोढौक्यते, here the rule of lengthening of this sutra, does not supersede, though it is subsequent, the rule of shortening in 7.4.59; so the diphthong औ is shortened to उ, and it is then gunated by 7.4.82. Secondly observe अचीकरत्, here इ is substituted in the reduplicate by 7.4.79 plus 7.4.93, and then this is lengthened by 7.4.94, the latter not superseding the former. Thirdly observe मीमांसते &c, where in मान् + सन् (III. I. 6), the reduplicate is lengthened, but that does not prevent the इ of 7.4.79. Fourthly observe अजीगणन्, where the ई substitute 7.4.97 does not supersede the sutra 7.4.60, by which the ण् of गण् is elided.,