1. 4 on class
2. 1 in definition
3. 1 in notes

On grammatical class:

vi'a

dimensionality of space interval tense: 2-space interval; throughout an area.

vi'e

dimensionality of space interval tense: 4-space interval; throughout a spacetime.

vi'i

dimensionality of space interval tense: 1-space interval; along a line.

vi'u

dimensionality of space interval tense: 3-space interval; throughout a space.

In definition:

cmavrvi'a

x₁ is the selma'o "VIhA".

In notes:

ve'arda

x₁ is a part of Lojban text representing rule 'space-interval' according to the first edition of the book 'The Complete Lojban Language'.