8.3.116
स्तम्भुसिवुसहां चङि
Operational rule vidhi
The ष् substitution does not take place in the reduplicated Aorist of the roots 1. स्तम्भ् 2. सिव् and 3. सह.
Word by word (padaccheda)
Target स्तम्भु- सिवु- सहाम् ṣaṣṭhī · bahuvacanaRight context चङि saptamī · ekavacana
- Target Ṣaṣṭhī (6th case): names what gets replaced, "in place of X" (1.1.49 षष्ठी स्थानेयोगा).
- Right context Saptamī (7th case): "when X follows", the operation applies to what precedes (1.1.66 तस्मिन्निति निर्दिष्टे पूर्वस्य). Also a condition or domain ("in the sense of").
Full reading
स्तम्भु-
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
Commentary
The ष् substitution does not take place in the reduplicated Aorist of the roots 1. स्तम्भ् 2. सिव् and 3. सह।
The root स्तम्भ required ष change by 8.3.67, and the roots सिव and सह by 8.3.70. Thus पर्यतस्तम्भत्, अभ्यतस्तम्भत् ॥ सिव :- पर्यसीषिवत्, न्यसीषिवत् ॥ सह :- पर्यसीषहत्, व्यसीषहत् ॥
Vart:- This prohibition refers to the ष change that is caused by an Upasarga and not to the reduplicate change, as we have illustrated in the above example.
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.