e is substituted for a of 1. tṝ 2. phala 3. bhaja and 4. trapa and the reduplicate is elided when the affixes of the liṭ (Perfect Tense) having an indicatory k (or ṅ) follow, as well as when thal of the liṭ (Perfect Tense) having the augment iṭ follows.,
Thus तेरतुः, तेरुः, तेरिथ, फेलतुः, फेलुः, फेलिथ, भेजतु, भेजुः, भेजिथ, त्रेपे, त्रेपते, त्रेपिरे ॥ In the case of तॄ the rule applies to the अ obtained by Guna, contrary to 6.4.126, in फल् and भज् the rule, that no different substitute should be in the reduplicate, is not adhered to, and in त्रप the अ does not stand between two simple consonants.
Vart:- It should be stated that the rule applies to श्रन्थ also:- as, श्रेथतुः, श्रेथुः ॥,