17.11. Mathematical uses of lerfu strings

This chapter is not about Lojban mathematics, which is explained in Chapter 18 , so the mathematical uses of lerfu strings will be listed and exemplified but not explained.

Example 17.34. 

li .abu du li by. su'i cy.
the-number a equals the-number b plus c

a = b + c

Example 17.35. 

li .y.bu du li ma'o fy. boi xy.
the-number y equals the-number the-function f of x
y = f(x)

Note the boi here to separate the lerfu strings fy. and xy..

Example 17.36. 

le vi ratcu ny.moi le'i mi ratcu
the here rat is-nth-of the-set-of my rats

This rat is my Nth rat.

Example 17.37. 



Example 17.38. 

xy. xi ky.
x sub k


Example 17.39. 

vei ny. [ve'o] lo prenu
( n ) persons

The parentheses are required because ny. lo prenu would be two separate sumti, ny. and lo prenu. In general, any mathematical expression other than a simple number must be in parentheses when used as a quantifier; the right parenthesis mark, the cmavo ve'o , can usually be elided.

All the examples above have exhibited single lerfu words rather than lerfu strings, in accordance with the conventions of ordinary mathematics. A longer lerfu string would still be treated as a single variable or function name: in Lojban, .abu by. cy. is not the multiplication a × b × c but is the variable abc. (Of course, a local convention could be employed that made the value of a variable like abc , with a multi-lerfu-word name, equal to the values of the variables a , b , and c multiplied together.)

There is a special rule about shift words in mathematical text: shifts within mathematical expressions do not affect lerfu words appearing outside mathematical expressions, and vice versa.