The augment suṭ is placed before ka even when sam , pari , and upa are followed by the verb kṛ and the sense being that of combining.,
The word समवाय means aggregation. Thus तत्र नः संष्कृतम् तत्र नः परिष्कृतम्, तत्र नः उपष्कृतम् = समुदितम् that is 'we assembled there'.,