The vocalisation may optionally take place when vye preceded by pari takes the affix lyap,
Thus परिवीय यूपम् or परिव्याय ॥ The augment तुक् presented by (VI. I. 71) is debarred by (VI. 4. 2.) which causes the lengthening of the vowel: since 6.4.2 is subsequent to 6.1.71.,