v and y preceded by a or ā and the end of a pada are elided before an aś letter (vowels and soft-consonants) according the opinion of śākalya,
As क आस्ते or कयास्ते, काक आस्ते or काकयास्ते, अस्मा उद्धर or अस्मायुद्धर, द्वावत्र or द्वा अत्र, असावादित्यः or असा आदित्यः ॥
The name of Sakalya is used to make it an optional rule. Therefore, where there is not the lighter articulation of व् and य् by the last sutra, there also in the other alternative the fuller sounds of व् and य् are heard. Thus there are three forms, heavy व् and य्, light व् and य् and elision of व् and य् ॥
When व् and य् are preceded by ओ, then there is elision by the next sutra compulsorily.,