In selecting the appropriate equations from the description of the whole corpus […], we adjust the inclusion numbers to satisfy the chain of equations. This is based on the definition of the numbers, which indicates that numbers on the left hand side of the equation represent themselves or any lower number. Therefore, 'V ³Vυ=V⁴', which is one of the equations of our English analysis, represents 'V ²Vυ=V⁴' and 'V ¹Vυ=V⁴' as well as itself.
- Harris (1951), a pag.279, n.39