Grammatical Sūtra: पूर्वपदात्‌ pūrvapadāt‌
Individual Word Components: pūrvapadāt
Sūtra with anuvṛtti words: pūrvapadāt pūrvatra (8.2.1), asiddham (8.2.1), saṁhitāyām (8.2.108), apadāntasya (8.3.55), mūrdhanyaḥ (8.3.55), saḥ (8.3.56), iṇkoḥ (8.3.57), ekeṣām (8.3.102), chandasi (8.3.103)
Type of Rule: niyama
Preceding adhikāra rule:8.3.64 (1sthādiṣv abhyāsena ca abhyāsasya)

Description:

In the Chhandas, according to some, ((s)) is changed to ((ṣ)), when it stands in the beginning of a second word, preceded by a word ending in ((i)) &c. Source: Aṣṭādhyāyī 2.0

[In the domain of Chándas 105, according to some grammarians 104, the substitute retroflex 55 sibilant ṣ 39 replaces the dental sibilant s 56, after 1.1.67] a prior member (pūrva-pad-āt) [in composition 80, ending in 1.1.72 a vowel other than phoneme-class /a/ 57, in continuous utterance 2.108]. Source: From Aṣṭādhyāyī of Pāṇini In Roman Transliteration translated by Sumitra M. Katre, Copyright © 1987. Courtesy of the University of Texas Press.

Source:Srisa Chandra Vasu's Aṣṭādhyāyī of Pāṇini

Anuvṛtti: 8.3.55, 8.3.57, 8.3.104, 8.3.105, 8.3.56

Kāśikāvṛttī¹: sanoteḥ anakārāntasya sakārasya mūrdhanyādeśo bhavati. goṣāḥ. nṛṣāḥ. anaḥ iti ki   See More

Kāśikāvṛttī²: pūrvapadāt 8.3.104 chandasi iti vartate, ekeṣām iti ca. pūrvapadasthānnimittāt    See More

Nyāsa²: yajuṣyekeṣām?. , 8.3.106 "yajuṣi" iti. yajurvede. atra pādā na sambhav   See More

1.Source: Arsha Vidya Gurukulam
2.Source: Sanskrit Documents