Grammatical Sūtra: निव्यभिभ्योऽड्व्यावये वा छन्दसि nivyabhibhyo'ḍvyāvaye vā chandasi
Individual Word Components: nivyabhibhyaḥ aḍ‍vyāvaye vā chandasi
Sūtra with anuvṛtti words: nivyabhibhyaḥ aḍ‍vyāvaye vā chandasi 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), na (8.3.108)
Type of Rule: vidhi
Preceding adhikāra rule:8.3.64 (1sthādiṣv abhyāsena ca abhyāsasya)

Description:

The ((ṣ)) is optionally substituted in the Chhandas after the prepositions ((ni)), ((vi)) and ((abhi)), when the augment ((aṭ)) intervenes. Source: Aṣṭādhyāyī 2.0

In the domain of Chándas [the substitute retroflex 55 sibilant ṣ 39 does not 110] optionally (vā) replace [dental sibilant s 56] with the intervention of [the initial increment] áṬ of a verbal theme, co-occurring [after 1.1.67] the preverbs ní-°, ví-°, or abhí-° [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, 8.3.110, 8.3.56