## 11.5. Amount abstractions

The following cmavo is discussed in this section:

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 11.

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:

*ni* 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.