Karnatakabhashabhushana 2.3.2

2.3.2

Because of the principle that an injunction undertaken when [an operation] is already established serves as a restriction, this rule is for the purpose of restriction: if there should be elision of a vowel belonging to a stem, it is only of the vowels u and ē, not of another. Because of the governing rule of vowels, here the elision of vowels is restricted, not indeed the stem.