y preceded by o is elided before an aś letter (vowels and soft-consonants) according the opinion of gārgya ,
There can be no व् preceded by ओ, so only य् is taken in explaining the sutra. Thus भो अत्र, भगो अत्र, भो इदम्, भगो इदम् ॥
The making of it a separate sutra, is for the sake of indicating that this is a necessary (nitya) rule and not a vibhasha rule. The name of Gargya is used simply honoris causa (pujartha). The elision of laghu-prayatna य्, which 8.3.19 would have otherwise caused, is hereby prohibited. So that
laghu pratyatnatara य् does come also. As भो अत्र or भोयत्र, भगो अत्र or भगोयत्र, अघो अत्र and अघोयत्र ॥
According to others every kind of य् (whether heavy or light) is to be elided: and भोयत्र is not valid in their opinion.,