The affix ṭhak comes after the words niṣka etc., when they are not parts of a compound, the sense of the affix being that taught in the subsequent sutras up to [[5.1.63]].,
The word आर्हात् is understood in this sutra also. This ठक् debars ठञ्. Thus नैष्किक꣡म्, पाणिक꣡म्, पादिक꣡म्, माषिक꣡म् ॥
Why do we say असमासे 'when not compounds'? Observe प꣡रमनैष्किकम् उ꣡त्तमनैष्किकम् formed by ठञ् (V. I. 18.) Compare 7.3.17 by which the Vriddhi of the second term takes place and not of the first.
Q. Is not the employment of the word असमासे in the Sutra redundant? For by the maxim ग्रहणवता प्रातिपदिकेन तदन्तविधिर्नास्ति \that which cannot possibly be anything but a pratipadika, does, contrary to 1.1.72, not denote that which ends with it, but it denotes only itself;\ the pratipadika निष्क being especially mentioned in the sutra, the rule will apply to the word निष्क and not to a word ending with निष्क ॥
A. The employment of the word असमासे in this Sutra, indicates by implication jnapaka), that in spite of the above maxim, the तदन्तविधिः 1.1.72 applies in the previous sutras, while in the subsequent sutras its does not. As उगवादिभ्यो यत् 5.1.2, the यत् applies not only to गो &c but to words ending in गो &c. As गव्यम् and सुगव्यम्, अतिसुगव्यम् ॥ Not only अपूप्यम् अपूपीयम् (V. I. 4.) but also यवापूप्यम्, यवापूपीयम् ॥ Not only दन्त्यम् (V. 1. 6.) but also राजदन्त्यम् ॥
While in the sutras subsequent to this 5.1.20, the tadanta-vidhi applies only to words preceded by a Sankhya and that also in Sutras upto 5.1.115 and not there after as, द्वैपारायणिकः and त्रैपारायणिक 5.1.72. Even in this latter case, when an affix is elided by लुक् the tadanta vidhi does not apply. Thus द्वाभ्यां शूर्पाभ्यां क्रीतं = द्वि शूर्प + ठञ् (V. I 18) = द्विशूर्पम्, the affix being elided by 5.1.28. Now in forming a tertiary derivative from this word द्विशूर्पम्, the tadanta vidhi will not apply. Thus द्विशूर्पेण क्रीतं, here what affix are we to subjoin? If tadanta vidhi applied, we get the affix अञ् 5.1.26 in the alternative. But tadanta vidhi not applying, we get the general affix ठञ् 5.1.8 and have द्विशौर्पिकम् ॥ Here the affix ठञ् is not elided by 5.1.28, as there is no Dvigu compounding. The above rule is summarised in the following ishti प्राग्वतेः संख्यापूर्वपदानां तदन्तग्रहणमलुकि ॥
The words 1. निष्क, 2. पण, 3. माष, 4. वाहद्रोण and 5. षष्टि belong to निष्कादि class.,