So far, we have concentrated on selecting the places to go into the place structure of a lujvo. However, this is only half the story. In using selbri in Lojban, it is important to remember the right order of the sumti. With lujvo, the need to attend to the order of sumti becomes critical: the set of places selected should be ordered in such a way that a reader unfamiliar with the lujvo should be able to tell which place is which.
If we aim to make understandable lujvo, then, we should make the order of places in the place structure follow some conventions. If this does not occur, very real ambiguities can turn up. Take for example the lujvo jdaselsku, meaning “prayer”. In the sentence
we must be able to know if Dong is the person making the prayer, giving the meaning
or is the entity being prayed to, resulting in
We could resolve such problems on a case-by-case basis for each lujvo (Section 12.14 discusses when this is actually necessary), but case-by-case resolution for run-of-the-mill lujvo makes the task of learning lujvo place structures unmanageable. People need consistent patterns to make sense of what they learn. Such patterns can be found across gismu place structures (see Section 12.16), and are even more necessary in lujvo place structures. Case-by-case consideration is still necessary; lujvo creation is a subtle art, after all. But it is helpful to take advantage of any available regularities.
We use two different ordering rules: one for symmetrical lujvo and one for asymmetrical ones. A symmetrical lujvo like balsoi (from Section 12.5) has the places of its tertau followed by whatever places of the seltau survive the elimination process. For balsoi, the surviving places of banli are b2 and b3, leading to the place structure:
just what appears in Example 12.11. In fact, all place structures shown until now have been in the correct order by the conventions of this section, though the fact has been left tacit until now.
The motivation for this rule is the parallelism between the lujvo bridi-schema
and the more or less equivalent bridi-schema
where gi'e is the Lojban word for “and” when placed between two partial bridi, as explained in Section 14.9.
Asymmetrical lujvo like gerzda, on the other hand, employ a different rule. The seltau places are inserted not at the end of the place structure, but rather immediately after the tertau place which is equivalent to the first place of the seltau. Consider dalmikce, meaning “veterinarian”: its veljvo is danlu mikce, or “animal doctor”. The place structures for those gismu are:
and the lujvo place structure is:
Since the shared place is m2=d1, the animal patient, the remaining seltau place d2 is inserted immediately after the shared place; then the remaining tertau places form the last two places of the lujvo.