The luk elision of gotra (Patronymic) affixes in plural, which have been enjoined by sūtras yaskādibhyo gotre [[2.4.63]] etc. and the rest is prohibited, when the affix has an initial vowel and it has the sense of the various affixes taught antecedent to tena dīvyati khanati jayati jitam [[4.4.2]].,
Thus the plural of गार्ग्य is गर्गाः 2.4.64. But the disciples of गर्गाः will be formed by the affix छ (IV. 21. 114) which is a pragdivyatiya affix and for the purposes of adding this affix the base will be considered to be गार्ग्यः as if there was no elision. Thus गार्ग्याः + छ = गार्गीयाः 7.1.2 and 6.4.151, and not गर्गीयाः । Similarly वात्सीयाः, आत्रयीयाः, खारपायणीयाः 'disciples of Vatsyas, Atreyas, Kharpayanas.'
Why do we say \गोत्रे\ i. e. \when the Gotra affix is elided\? Observe कौबलम्, बादरम् ॥ Here the affix denoting \fruit\ is elided by लुक् by Sutra 4.3.163. Then when the pragdivytiya affix अण् is added, the luk-elision is maintained. Thus the fruit of बदरी is बदरम्; from which बादरम् 'belonging to or coming from the jujube-fruit.'
Why do we say \having an initial vowel\? Observe गर्गेभ्य आगतम् = गर्गरूप्यम् and not गार्गरूप्यम्; and गर्गमयम्; and not गार्गमयम् ॥ Here the affix रूप्य, a pragdivyatiya affix taught in sutra 4.3.81 does not begin with a vowel; therefore it is added to गर्ग and not गार्ग्य ॥ Similarly the next affix मयट् 4.3.82.
Why do we say \when it has the sense of a pragdivyatiya affix\ ? Thus गर्गेभ्यो हितम् = गर्गीयम् 'who is fit for the Gargas'. Here the affix छ 5.1.1 has the sense of 'suitable for that', as taught in Sutra (V. I. 5) not one of the pragdivyatiya senses. Hence the luk elision is maintained.
The Gotra-affixes are taught to be elided in the plural only: and when after such supposed elision a Singular or Dual Person is intended, this rule will still apply and there will be no elision. Thus बिद will form its Gotra derivative by अञ् 4.1.104 as बिद + अञ् = बैदः ॥ The plural of बैद will be बिदाः by the elision of अञ् ॥ One yuvan or two yuvan descendants of these बिदाः will be formed by the affix इञ् 4.1.95, for the application of which the word बिदाः will be supposed not to have lost its अञ्, therefore इञ् will be added to बैद, thus बैद + इञ्; then this इञ् is elided by 2.4.58. The resultant form is बैदः, बैदो ॥ The many descendants (in the plural) of one बैदः or two बैदः will be बिदाः ॥,