deriv SD cv (212) ashtadhyayi.com hei.de L 212 ETT STT a 7.1.53 ALPH OLDHOMEPAGE NEWHOMEPAGE

tres trayaH त्रेस्त्रयः ONPANINI 71053

Replace tri- त्रिॱ by traya- त्रयॱ before /Am.

Only example:

tri- त्रिॱ mn + /Am
→ traya त्रय + /Am by this rule
→ traya त्रय + /nAm by hrasvanadyAp... >
→ trayA त्रया + /nAm by nAmi +
→ traya + NAm णाम् by /Natvam
→ trayANAm त्रयाणाम् "of three"

In the f we get **tisRNAm तिसृणाम्.