ये चाभावकर्मणोः

Operational rule vidhi

The syllable अन् of a अङ्ग (stem) ending in अन् remains unchanged before a तद्धित affix beginning with य् when it does not denote existence in abstract of the avocation of someone.

Word by word (padaccheda)

Right context ये saptamī · ekavacanaIndeclinable च avyayaRight context अ- भावकर्मणोः saptamī · dvivacana

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").
Indeclinable An avyaya such as च "and", वा "optionally", न "not".

Dotted words are technical terms. Hover or tap one to see its card.

Full reading

ये च अ-भावकर्मणोः

Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.

Commentary

The syllable अन् of a अङ्ग (stem) ending in अन् remains unchanged before a तद्धित affix beginning with य् when it does not denote existence in abstract of the avocation of someone.
Thus सामसु साधुः = सामन्यः, ब्राह्मण्यः ॥ But राज्ञो भावः कर्म वा = राज्यम् ॥ राजन् belongs to Purohitadi class and takes यक् 5.1.128.

Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.