## 17.9. lerfu words as pro-sumti

So far, lerfu words have only appeared in Lojban text when spelling out words. There are several other grammatical uses of lerfu words within Lojban. In each case, a single lerfu word or more than one may be used. Therefore, the term lerfu string is introduced: it is short for sequence of one or more lerfu words.

A lerfu string may be used as a pro-sumti (a sumti which refers to some previous sumti), just like the pro-sumti ko'a, ko'e, and so on:

Example 17.21.

 .abu prami by.
 A loves B

In Example 17.21, .abu and by. represent specific sumti, but which sumti they represent must be inferred from context.

Alternatively, lerfu strings may be assigned by goi, the regular pro-sumti assignment cmavo:

Example 17.22.

 le gerku goi gy. cu xekri .i gy. klama le zdani
 The dog, or G, is black. G goes to the house.

There is a special rule that sometimes makes lerfu strings more advantageous than the regular pro-sumti cmavo. If no assignment can be found for a lerfu string (especially a single lerfu word), it can be assumed to refer to the most recent sumti whose name or description begins in Lojban with that lerfu. So Example 17.22 can be rephrased:

Example 17.23.

 le gerku cu xekri. .i gy. klama le zdani
 The dog is black. G goes to the house.

(A less literal English translation would use D for dog instead.)

Here is an example using two names and longer lerfu strings:

Example 17.24.

 la stivn. mark. djonz. merko Steven Mark Jones is-American.
 .i la .aleksandr. paliitc. kuzNIETsyf. rusko Alexander Pavlovitch Kuznetsov is-Russian.
 .i symyjy. tavla .abupyky. bau la lojban. SMJ talks-to APK in Lojban.

Perhaps Alexander's name should be given as ru'o.abupyky instead.

Example 17.25.

 .abu dunda by. cy. A gives B C

Does this mean that A gives B to C? No. by. cy. is a single lerfu string, although written as two words, and represents a single pro-sumti. The true interpretation is that A gives BC to someone unspecified. To solve this problem, we need to introduce the elidable terminator boi (of selma'o BOI). This cmavo is used to terminate lerfu strings and also strings of numerals; it is required when two of these appear in a row, as here. (The other reason to use boi is to attach a free modifier – subscript, parenthesis, or what have you – to a lerfu string.) The correct version is:

Example 17.26.

 .abu [boi] dunda by. boi cy. [boi]
 A gives B to C

where the two occurrences of boi in brackets are elidable, but the remaining occurrence is not. Likewise:

Example 17.27.

 xy. boi ro [boi] prenu cu prami X all persons loves.
 X loves everybody.

requires the first boi to separate the lerfu string xy. from the digit string ro.