The affixes ṇamul and ktvā come optionally after that verb which denotes the prior action, when both verbs have the same agent, provided that the following words are in composition - 1. agre 2. prathama 3. pūrva,
This is an Aprapta-vibhasha. The word 're-iteration' is not understood here. Thus अग्रे, प्रथमं, पूर्वं वा भोजं भुक्त्वा व्रजति 'having first eaten he goes'.
By using the word 'optionally' it is indicated, that the regular Tenses, such as the Present &c, may be employed also. Thus अग्रे भुङ्क्ते ततः व्रजति 'he eats first and then goes'.
Q-- The affixes of Lat (Present tense) &c. would have been applied by the rule of वाऽसरूप 3.1.94; why then use the word 'optionally'?
Ans.-- The very use of the word 'optionally' in this sutra indicates the existence of this Paribhasha :- \The rule (III. I. 94) has no concern with the affixes ktva and namul, when both these affixes are enjoined at one and the same time by a single rule.\
Therefore, we cannot apply 3.1.94 and use the affixes Lat &c, when 're-iteration' is meant That is the exclusive province of क्त्वा and णमुल् ।
Why is not here the Upapada compounding by rule 2.2.20? For an answer to this, see the commentary on 2.2.20. Had only णमुल् been enjoined by this sutra, and not क्त्वा also, then we could have formed the उपपद समास, for such is the force of the word एव in that sutra.,