काशिका वृत्ति (आचार्य वामन एवं जयादित्य - अष्टाध्यायी सूत्र-वृत्ति सम्पूर्ण सान्वय सटीक)

" and "इतरस्य त्वीत्वम्": In 7.4.55 (आप्ज्ञप्यृधामीत्): "ज्ञपेः..." Wait! What roots are in the sutra? आप्, ज्ञपि, ऋध्! Notice: the sutra says "ज्ञपि", NOT "ज्ञ"! Why "ज्ञपि" with 'इ'? Because it is the causative/curādi of ज्ञप्: "ज्ञपि मित्" (पुक) -> ज्ञप् + णिच् -> ज्ञपि! Now, ज्ञपि ends in 'इ' (णिच्). When सन् follows: ज्ञपि + स + लट्. Now, two rules apply:

1. "णेरनिटि" (6.4.51) -> णि-लोप (लोपः).
2. "आप्ज्ञप्यृधामीत्" (7.4.55) -> अच ईत् (ईत्वम्). Which applies first? णि-लोप is parasaptamī / paratvāt? Wait, "णेरनिटि" is 6.4.51. "आप्ज्ञप्यृधामीत्" is 7.4.55. By paratva, 7.4.55 (ईत्वम्) would apply! Wait, if ईत्व applies, it replaces 'अ' of ज्ञप् with 'ई', then णि-लोप happens, etc. Or if णि-लोप applies