## 18.19. Other uses of mekso

The following cmavo are discussed in this section:

 me'o LI the mekso nu'a NUhA operator to selbri mai MAI utterance ordinal mo'o MAI higher order utterance ordinal roi ROI quantified tense

So far we have seen mekso used as sumti (with li), as quantifiers (often parenthesized), and in MOI and ME-MOI selbri. There are a few other minor uses of mekso within Lojban.

The cmavo me'o has the same grammatical use as li but slightly different semantics. li means the number which is the value of the mekso ... , whereas me'o just means the mekso ... So it is true that:

Example 18.128.

 li re su'i re du li vo The-number two plus two equals the-number four. 2 + 2 = 4

but false that:

Example 18.129.

 me'o re su'i re du me'o vo The-mekso two plus two equals the-mekso four.
 “2 + 2” = “4”

since the expressions 2 + 2 and 4 are not the same. The relationship between li and me'o is related to that between la .djan. , the person named John, and zo .djan. , the name John

The cmavo nu'a is the inverse of na'u , and allows a mekso operator to be used as a normal selbri, with the place structure:

x1 is the result of applying (operator) to x2, x3, ...

for as many places as may be required. For example:

Example 18.130.

 li ni'umu cu nu'a va'a li ma'umu The-number -5 is-the-operator negation-of the-number +5.

uses nu'a to make the operator va'a into a two-place bridi

Used together, nu'a and na'u make it possible to ask questions about mekso operators, even though there is no specific cmavo for an operator question, nor is it grammatical to utter an operator in isolation. Consider Example 18.131 , to which Example 18.132 is one correct answer:

Example 18.131.

 li re na'u The-number two applied-to-selbri
 mo re du li vo which-selbri? two equals the-number four. 2 ? 2 = 4

Example 18.132.

 nu'a su'i
 plus

In Example 18.131 , na'u mo is an operator question, because mo is the selbri question cmavo and na'u makes the selbri into an operator. Example 18.132 makes the true answer su'i into a selbri (which is a legal utterance) with the inverse cmavo nu'a. Mechanically speaking, inserting Example 18.132 into Example 18.131 produces:

Example 18.133.

 li re na'u nu'a The-number two (the-operator the-selbri
 su'i re du li vo plus) two equals the-number four.

where the na'u nu'a cancels out, leaving a truthful bridi

Numerical free modifiers, corresponding to English firstly , secondly , and so on, can be created by suffixing a member of selma'o MAI to a digit string or a lerfu string. (Digit strings are compound cmavo beginning with a cmavo of selma'o PA, and containing only cmavo of PA or BY; lerfu strings begin with a cmavo of selma'o BY, and likewise contain only PA or BY cmavo.) Here are some examples:

Example 18.134.

 pamai
 firstly

Example 18.135.

 remai
 secondly

Example 18.136.

 romai all-ly
 lastly

Example 18.137.

 ny.mai
 nth-ly

Example 18.138.

 pasomo'o
 nineteenthly (higher order) Section 19

The difference between mai and mo'o is that mo'o enumerates larger subdivisions of a text. Each mo'o subdivision can then be divided into pieces and internally numbered with mai. If this chapter were translated into Lojban, each section would be numbered with mo'o. (See Section 19.7 for more on these words.)

A numerical tense can be created by suffixing a digit string with roi. This usage generates tenses corresponding to English once , twice , and so on. This topic belongs to a detailed discussion of Lojban tenses, and is explained further in Section 10.9.

Note: the elidable terminator boi is not used between a number and a member of MAI or ROI.