8.3.118
सदेः परस्य लिटि
Operational rule vidhi
The ष् substitution does not take place in the स् of सद् and ष्वञ्ज् after the reduplicate in the लिट् (Perfect Tense).
Word by word (padaccheda)
Target सदेः ṣaṣṭhī · ekavacanaTarget परस्य ṣaṣṭhī · ekavacanaRight context लिटि 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
सदेः परस्य लिटि
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 स् of सद् and ष्वञ्ज् after the reduplicate in the लिट् (Perfect Tense).
In the Perfect, when these words are reduplicated, there are two स's, as ससाद and सस्वंज ॥ After a preposition, the first स will be changed to ष, but not so the second. Thus अभिषसाद, परिषसाद, निषसाद, विषसाद, परिषस्वजेः, परिषस्वजाते, परिषस्वजिरे, अभिषस्वजे ॥ The nasal of स्वंज is elided though here, the लिट् affix is not कित्, because it ends in a compound vowel 6.4.24, 1.2.5 and 1.2.6.
The word स्वंज does not occur in the sutra, but has been inserted in it by the author of Kasika from the following Vartika:- सदो लिटि प्रतिषेधे स्वञ्जे रूपसंख्यानं कर्तव्यम् ॥
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.