The affixes ṭhak and chas come after vṛddha word bhavat , in the remaining senses.,
The word भवत् is a Vriddha word because it belongs to tyadadi class (I. I. 74). This rule debars छ of the last aphorism. In the affix, छस्, the final स् is indicatory, showing that the word भवत् before this affix gets the designation of Pada पद 1.4.16. Thus भवत् + ठक् = भावत्कः; भवत् + छस् = भवतीयः ॥
But when the word भवत् is not treated as Vriddha, then it takes the general affix अण्; as भावतः ॥ This is the case when भवत् is derived by affixing शतृ to भू ॥,