न ङिसम्बुद्ध्योः

(But such न्) is not elided in the Locative -7th case and Vocative Case singular.
This debars the elision of न्, which otherwise would have taken place by the preceding sutra. The examples of non-elision, of न् in the Locative singular are to be found in the Vedas. As परमे व्योमन् (Rig. I.164.39), आर्द्रे चर्मन्, लोहिते चर्मन् ॥ Here the sign of the Locative, namely इ (ङि) is elided by 7.1.39. In the Vocative Singular, the न् is not elided, as हे राजन्, हे तक्षन् ॥

Question: When ङि or the Vocative is elided, the preceding stem is no longer a Pratipadika, and the stem does not get the designation of पद before the affix but is भ, hence where is the necessity of making the present prohibitory rule, when the elision of न् would not have taken place in the Locative and Vocative singular, by any rule ?

Answer:- The very fact of the prohibition of the elision of न्, as contained in this aphorism, indicates by implication (jnapaka), that a word retains the designation of pratipadika, though an affix has been elided after it and though such elided affix may produce its effect (1.2.45 read with 1.1.62). Nor will such elided affix give the designation of Bha (भ) to such a stem. Thus राज्ञः पुरुषः = राजपुरुषः, here the न् is elided by considering the word राजन् as a pratipadika, even after the elision of the Genitive affix in the compound, and it is not a Bha, which would have required the elision of अ by 6.4.134.

Vart:- Prohibition of the prohibition must be stated, when the Locative word is followed by another word in a compound. That is, when a compound is a Locative Tatpurusha, the न् is elided : as, चर्मणि तिला अस्य = चर्म तिलः ॥

In हे राजवृन्दारक ! the first member राजन् does not retain its न् by the present sutra, because the whole compound, as such, is in the Vocative case, and not the word राजन् ॥ In fact, there can be no compound, which in its analysis, will give the first member as a Vocative word.

Vart:- Optionally so in the neuter nouns. As, हे चर्मन्, हे चर्म !