द्यतिस्यतिमास्थामित्ति किति

Operational rule vidhi

Short इ is substituted for the final of 1. दो 2. सो 3. मा and 4. स्था before an affix beginning with त् and having an indicatory क् .

Word by word (padaccheda)

Target द्यतिस्यतिमास्थाम् ṣaṣṭhī · bahuvacanaSubstitute / term prathamā · ekavacanaRight context ति saptamī · ekavacanaRight context किति saptamī · ekavacana

Target Ṣaṣṭhī (6th case): names what gets replaced, "in place of X" (1.1.49 षष्ठी स्थानेयोगा).
Substitute / term Prathamā (1st case): in operational rules, the substitute or the thing introduced; in definitions, the term or its referent.
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").

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

Full reading

द्यतिस्यतिमास्थाम् ति किति

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

As a rewrite rule (sketch from case endings)

द्यतिस्यतिमास्थाम् → / ति किति

Replace dyatisyatimāsthām with it when ti kiti follows. Inherited words (anuvṛtti) may add further conditions.

Commentary

Short इ is substituted for the final of 1. दो 2. सो 3. मा and 4. स्था before an affix beginning with त् and having an indicatory क् ।
As निर्दितः and निर्दितवान्; अवसितः and अवसितवान्, मितः and मितवान्; स्थितः and स्थितवान्, all with क्त and क्तवतु ॥ Why before त्? Observe अवदाय ॥ Why before a कित् affix? Observe अवदाता with तृच् ॥

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