A single consonantal sārvadhātuka affix gets the augment īṭ after as (asti) and after the Aorist character sic ,
As आसात्, आसीः; अकार्षीत्, असावीत् ॥ Why do we say a single-consonant affix? Observe अस्ति, अकार्षम् ॥
Vart:- Prohibition of the sthanivad-bhava must be stated when आह् is substituted for ब्रु 3.4.84, and भू for अस् 2.4.52, before the augment ईट् ॥ Therefore not here आत्थ and अभूत् ॥ The word आत्थ is thus formed. आह् + सिप् = आह् + थल् 3.4.84 = आथ् + थ 8.2.35 = आत् + थ 8.4.55 = आत्थ ॥,