deriv SD cv (336) ashtadhyayi.com hei.de L 336 ETT STT a 6.3.128 ALPH OLDHOMEPAGE NEWHOMEPAGE

vizvasya vasu;rAToH

विश्वस्य वसुॱराटोः ONPANINI 63128

Lengthen /vizva- before vasu वसु **rAT- राट्.

This vasu वसु is NOT the /vasu affix —

/vizva- + vasu वसु → vizvAvasu- विश्वावसुॱ

This **rAT- राट् is the padafinal form of **rAj- राज्, which is a rootnoun with the same meaning as **rAjan- राजन्, namely "one who rules" or "one who shines".

/vizva- + **rAj- राज् + /su
→ /vizva- + rAT राट् by halGyAbbhyodIrgh..., vrazcabhrasjas..., jhalAJjazonte, normalizing
→ !**vizvArAT विश्वाराट् "universal emperor", by this rule

But when **rAj- राज् is not padafinal, it does not become rAT राट्, so there is no lengthening —

/vizva- + **rAj- राज् + /au
→ !**vizvarAjau विश्वराजौ