According to the opinion of the Eastern Grammarians, the affix ktvā is added to the root men 'to exchange' when the sense is that of interchange, (though the action denoted by the former word is not prior to the action denoted by the latter word).,
Thus अपमित्य याचते 'having offered an exchange, he asks' अप + मे + क्त्वा = अप + मा + ल्यप् = अप + मि + तुक् + य 6.1.45 and 6.1.71 = अप + मित्य 7.4.40. This is an optional rule, as the phrase 'according to the northern' indicates. So we have in the alternative, याचित्वाऽपयमते 'having asked he exchanges'; and this is the more general use of ktva; namely, it comes after that verb which is concerned about a time anterior to that of the other; see rule 21. The present sutra is an exception to 3.4.21.
The root मेङ् has been exhibited in the sutra as माङ्, with the vowel आ instead of ए. This indicates the existence of the following Paribhasha:--
\A root, which, when destitute of anubandhas, ends in either ए, ओ or ऐ, must not be considered to have ceased to end in either ए, ओ, or ऐ, when an anubandha has been attached to it.\ By this Paribhasha दैप् must be regarded as ending in ऐ, and as therefore आ may be substituted for the vowel ऐ 6.1.45, even while प् remains, दैप् does assume the form दाप् and is consequently; by the prohibition अदाप् in sutra 1.1.20, forbidden to be termed घु ।,