## 11.5. Amount abstractions

The following cmavo is discussed in this section:

 ni NU amount abstraction

Amount abstractions are far more limited than event or property abstractions. They really make sense only if the selbri of the abstracted bridi is subject to measurement of some sort. Thus we can speak of:

Example 11.34.

 le ni le pixra cu blanu [kei] the amount-of (the picture being-blue )
 the amount of blueness in the picture

because blueness could be measured with a colorimeter or a similar device. However,

Example 11.35.

 le ni la djein. cu mamta [kei] the amount-of (that-named Jane being-a-mother )
 the amount of Jane's mother-ness (?) the amount of mother-ness in Jane (?)

makes very little sense in either Lojban or English. We simply do not have any sort of measurement scale for being a mother.

Semantically, a sumti with le ni is a number; however, it cannot be treated grammatically as a quantifier in Lojban unless prefixed by the mathematical cmavo mo'e:

Example 11.36.

 li pa vu'u mo'e le ni the-number 1 minus the-operand the amount-of (
 le pixra cu blanu [kei] the picture being-blue )
 1 - B, where B = blueness of the picture

Mathematical Lojban is beyond the scope of this chapter, and is explained more fully in Chapter 18.

There are contexts where either property or amount abstractions make sense, and in such constructions, amount abstractions can make use of ce'u just like property abstractors. Thus,

Example 11.37.

 le pixra cu cenba le ka ce'u blanu [kei] The picture varies in-the property-of (X is blue ).
 The picture varies in being blue. The picture varies in blueness.

is not the same as

Example 11.38.

 le pixra cu cenba le ni ce'u blanu [kei] The picture varies in-the amount-of (X is blue ).
 The picture varies in how blue it is. The picture varies in blueness.

Example 11.37 conveys that the blueness comes and goes, whereas Example 11.38 conveys that its quantity changes over time.

Whenever we talk of measurement of an amount, there is some sort of scale, and so the place structure of ni abstraction selbri is:

x1 is the amount of (the bridi) on scale x2

Note: the best way to express the x2 places of abstract sumti is to use something like le ni ... kei be. See Example 11.62 for the use of this construction.