Praudhamanorama p209

p209

On "aci ra ṛtaḥ" (Pā. Sū. 7.2.100): On "of guṇa, lengthening, and the substitution of u": The substitution of r is an exception to the guṇa prescribed by "ṛto ṅi" (Pā. Sū. 7.3.111) in tisrastiṣṭhanti, to the homogeneous prior lengthening prescribed by "prathamayoḥ pūrvasavarṇaḥ" (Pā. Sū. 6.1.102) in tisraḥ paśya, and to the substitution of u prescribed by "ṛta ut" (Pā. Sū. 6.1.111) in priyatisraḥ āgataḥ, priyatisraḥ svam—this is the meaning; the purport is that in the consideration of what is to be blocked in general, everything that has presented itself within its own scope is blocked. But in the consideration of specific rules, by the maxim "madhye'pavādāḥ...", there would be blocking only of lengthening and the substitution of u, but not of guṇa. And the general and specific views, like the universal and individual views, are established according to the requirement of the target forms, as is clear in Kaiyaṭa and others.
As for what they explained—that the word apavāda implies blocking in general, and the intention is that it blocks even guṇa by prior conflict of rules—that is unfounded and strained.
As for what the author of the Prasāda said—that the meaning is that it is a blocker of guṇa by prior conflict of rules and of the other two by subsequent conflict of rules—that is incorrect, because the rule prescribing r has not found scope elsewhere. Nor can it be said that it has found scope in ṭā and os, because that is already accounted for by yaṇ.
On "because of qualifying tri and catur": The purport is that, because it is directly heard, the qualifier "in the feminine" qualifies only "of tri and catur", not the base.