When a case-affix beginning with a vowel follows, then the semi-vowel v is substituted for the final ū of a aṅga (stem) containing more than one syllable if the aṅga (stem) ends with a verbal root ending in ū not preceded by a conjunct consonant forming part of the root.,
As no roots at the end of a stem end in short उ, the latter is not mentioned in the translation. Thus खलपू 'a sweeper':- dual खलप्वौ, plural खलप्वः; so also शतस्वौ and शतस्वः, and सकृल्लू : dual सकृल्ल्वौ and सकृल्ल्वः ॥ But लुलुवतुः and लुलुवः before tense-affixes, (non-सुप्); लू - लुवौ, लुवः (because consisting of one syllable only), and कटप्रू - कटप्रुवौ, कटप्रुवः (because ऊ is preceded by a conjunct consonant forming part of the root). The rule does not apply if the first member is not a Gati or a Karaka word: as परमलूः- परमलुवौ and परमलुवः ॥,