TECH:Lujvo Place Structure paper, part 2.

[Nick Nicholas <nsn@MULLIAN.EE.MU.OZ.AU>]

2. Lujvo place selection

There are two ways of determining the arguments a lujvo will have. The first
is to postulate a place structure from the beginning, and see whether
eliminating places from the component gismu will lead to this structure. The
second is to start without any preconceptions on the final place structure,
and if the result of eliminating places doesn't convey the information desired,
try a new base tanru (veljvo). (Remember that the place structure *is* the
definition of meaning of a bridi in Lojban.) The few place structure
derivations published in ju'i lobypli have followed the first approach. In
this study, we will follow the second approach. We believe it encourages
better-made lujvo, whose intended meaning more closely and predictably relates
to the veljvo, without presupposing any knowledge.

In fixing the place structure of a lujvo, there are two criteria for
eliminating places from the component gismu:

* The place conveys redundant information.
* The place conveys irrelevant information.

Usually at least one place will be eliminated by redundancy. To explain why,
we will digress to consider the three main classifications of lujvo according
to place structure selection.

2.1. Lujvo classifications: be, je, belenu

2.1.1. Lujvo classifications: be, je

We postulate the hypothesis that all concepts expressable as tanru or lujvo
can also be expressed as bridi consisting of only gismu and cmavo (which we
will term the Gismu Deep Structure Hypothesis --- GDS Hypothesis.) This
hypothesis has been tacitly assumed in much Lojban work. For example, take
any ambiguous tanru.  We accept that, with a (syntactically) 'unambiguous'
language like Lojban, we should be able to express the various possible
meanings of a tanru unambiguously *in Lojban*. But how? We can either use
tanru, lujvo, or gismu to express the various bridi necessary. But tanru are
inherently ambiguous, and lujvo, though notionally unambiguous, are derived
from ambiguous tanru, giving a chicken-or-the-egg dead-end. The only possible
way remaining of unambiguous expression uses gismu and cmavo only. If we
accept that all ambiguous tanru can be disambiguated in Lojban, and the cmavo
{ta'unai} is to have any meaning, we must accept the GDS Hypothesis.

Let us take the dog-house tanru as an example. We can consider the following
strings of cmavo and gismu as possible disambiguations (GDS's) of {gerku
zdani}:

.i ta zdani be lo gerku
.i ta gerku gi'e zdani loimu'a civla
.i ta zdani neta'i lo'e gerku .iva'i ta gerku tarmi zdani

Now if the GDS Hypothesis is true, and the meaning of a tanru can be
expressed as a bridi where the seltanru and tertanru are in some *syntactic*
relation (broda je brode, broda be lo brode, broda pe lo brode), then at least
one place of the tertanru will contain information shared with a place in
the seltanru. Take the following two tanru and their GDS's as examples:

2.1) ta gerku zdani
ta zdani da poi ke'a gerku
ta zdani be lo gerku
z1 zdani z2=g1

2.2) ta blanu crino
ta blanu gi'e crino
ta blanu je crino
joigi da blanu gi da crino
b1=c1

(In the above examples, and in other examples in this paper, a letter x
followed by a number n denotes the nth place of the gismu starting with x.
Thus z1 is the first place of {zdani}.)

Most (though not all) tanru (and lujvo) can be analysed by one of the two
paradigms exemplified above. The seltanru and tertanru may be related to each
other in a GDS that can contain the word {be}. In that case, the seltanru
gismu contains information on a place of the tertanru. Such tanru are
termed asymmetrical in the tanru paper. Paradigm (2.1) is an example of this:
the bridi {gerku} gives further information on the sumti that is the {se
zdani} (le se zdani cu gerku). In effect, the place z2 denotes the same entity
as the place g1, and one needn't include both in the place structure of
{gekyzda}. Rather than have the place structure of {gekyzda} as:

gekyzda: ... ... is the entity housed in the doghouse; ... is the dog...

one has:

gekyzda: ... ... is the dog, which is the entity housed in the doghouse...

The entity housed and the dog are the same thing, in this definition of
"doghouse".

On the other hand, the two gismu may both be making claims that are true of
a given entity. In that case, the relationship may be expressed using the word
{je}, or some word with a similar semantic function. Such tanru are termed
symmetrical in the tanru paper. Paradigm (2.2) is an example of this: it is
true of the entity {da} that {da crino}, as well as that {da blanu}. Thus the
places b1 and c1 denote the same object, and again, one needn't include both
of them in the place structure of {blari'o}. Rather than having the place
structure:

blari'o: ... ... is blue; ... is green...

one has:

blari'o: ... ... is blue-and-green...

To emphasise the importance of GDS (which will become more apparent when we
discuss place ordering), we will term the paradigm exemplified by (2.1)
"be-tanru", and that exemplified by (2.2) "je-tanru".

2.1.2. Lujvo classifications: belenu

As a special case of the be-paradigm, consider (2.3):

(2.3) mi gasnu lenu le gerku cu citka loi guzme
I make the dog eat melons
mi nu lo gerku cu citka loi guzme kei gasnu
mi citka befa lo gerku beiloi guzme be'o gasnu
mi ctigau le gerku loi guzme
I feed the dog melons
g2=nu (c1 citka c2)

This is an example of a factitive, a predicate in which an agent brings
about an action described by the seltanru. 'Feed' is the factitive version
of 'to eat', for example; the transitive verb 'sink' (eg. I sink boats)
is the factitive of the intransitive 'sink' (eg. I sink). Factitives are
important in many languages, like Turkish and Esperanto. To eat in Esperanto
is mangxi, and to feed is mangxigi; to sink (intransitive) is sinki, and
to sink (transitive) is sinkigi. In Turkish, these verbs are respectively
yemek, yedirmek, batmak, batIrmak.

The advantage of having a form like {ctigau} instead of a form like {gasnu
lenu citka} are obvious in terms of succinctness. It is the only way to
express the relation "to feed" or "to drown something" in Lojban as a
straightforward sequence of sumti, without any nesting of abstract sumti.
We can predict that factitives will become quite prevalent in Lojban. As
another example, consider the verb "to record". The gismu {vreji} does not
correspond to this verb, but to the predicate "to be a record". If we
want to say "I record data", we need to say the equivalent of "I act so
that X is a record of data", {mi gasnu lenu da vreji loi datni}, or more
elegantly and succinctly, {mi veirgau da loi datni}.

The question becomes, how to form the lujvo. As the tanru form shows, the
relation is not between the two x1's, an eater (le citka) and an actor (le
gasnu). This is in contrast to je- and be-tanru. Rather, it is a
relationship between an actor and an *event* of eating (nu citka). The
obvious lujvo to be created is {nuncitkykeigau}, which is a straight-forward
be-tanru (le gasnu be le nuncitka). Consider the place structure for such a
lujvo. We would desire a place for the actor (g1), for the eater (c1), and
for the food (c2). {nuncitka}, according to an LLG recommendation published
in ju'i lobypli, has the place structure n1 c1 c2: the event of eating is x1,
the eater is x2, the food is x3. g2 is obviously the same as n1 (le se gasnu
cu nuncitka). However, it is possible to omit *both* g2 and n1 from the place
structure. Since we already know that we are discussing an act of eating, it
is redundant to leave in a place for the event of eating, when in Lojban we
typically consider an abstract sumti to be fully defined by its nested sumti.

Thus: nunctikeigau: agent x1 causes event x2 of x3 eating x4

is giving redundant information, when all the pertinent information about
the event x2 is given by arguments x3 and x4.

(This is not strictly true: the event of eating is specified by all the
arguments of the bridi {citka}, not just those built into its place
structure. There are time and location, for example: {nu mi citka ca la
pacicac. vi le ctikumfa}. The only argument for keeping a separate place
for {lenu citka} in {ctigau} is that the auxillary places of the event
{nu gasnu} can differ from those of {nu citka}. You can bring about someone
eating at 1 PM by an action of yours done at 9 am. The GDS is: {mi ca la
socac. gasnu lenu da citka ca la pacicac.} If we can keep a place for
{nu citka}, we can transform this to the lujvo: {mi ctigau lenu da citka ca
la pacicac. kei da ca la socac.} However, the redundancy in such a form is
so counterintuitive and disruptive, that it is best just to leave out the
abstract sumti place, and assume it is implicitly specified as much as is
necessary by the remaining lujvo places: {mi ctigau da ca la socac.} If we
need to specify the abstract sumti information more precisely, we can always
recourse to the GDS form.)

The resultant place structure,

nunctikeigau: agent x1 causes x2 to eat x3

does not discard essential information from the earlier structure (but see
above), and has the advantage of being much closer to Natural Language
factitives, and more intuitive. This is clear even in the English-language
description of the place structure.

For lujvo made with {gasnu}, the seltanru will usually specify an event. We
may thus omit the {nun} rafsi as implicit, and say simply

ctigau: agent x1 causes x2 to eat x3.

In this case, the place g2, the action performed, is equivalent to an
*abstraction* composed of all the places of {citka}. Rather than having a
be-lujvo, where a single place of the seltanru substitutes for a place in the
tertanru, we now substitute a *number* of places for that single place. This
particular paradigm we will call a belenu-lujvo.

be-lujvo, je-lujvo, and belenu-lujvo are the three types of lujvo Jim Carter
has identified in his dikyjvo work, which has been mentioned in the past in
ju'i lobypli and on lojban-list.

One must remember that belenu-lujvo are really an abbreviation of be-lujvo
based on abstract sumti. ctigau is really an abbreviation for nunctikeigau.
Furthermore, this is not an abbreviation that can be performed automatically.
there are only a few tertanru for which the rafsi {nun} is obviously implicit,
and to assume it too widely can lead to ambiguity. For example, the x2 of
{djica} is either an event or a simple sumti. {le soidji}, in the be-lujvo
interpretation, is someone who wants a soldier (le djica be lo sonci). In the
belenu-lujvo interpretation, it is someone who wants to be a soldier, a wannabe
soldier (le djica be lenu ri sonci), or perhaps someone who wants someone else
to be a soldier (le djica be lenu zo'e sonci). In these cases, saying
{nunsoidji} is a lot safer; in general, the user must be careful to use the
abbreviated form only when no reasonable ambiguity will result. This is much
clearer with bridi like {gasnu} and {rinka} than with, say, {djica} or {nelci}.
However, belenu-lujvo are powerful means in the language of rendering succinct
and manageable concepts out of quite verbose GDS forms.

To summarise:

In je-lujvo, the x1 of the tertanru is semantically "doubled up" by (denotes
an object identical to, or is also described by) the x1 of the seltanru, so
it shouldn't be necessary for both these places to appear in the lujvo place
structure.

In be-lujvo, the x2 of the tertanru (typically; sometimes, the x3) is doubled
up by the x1 of the seltanru: again, the two places needn't both appear in
the lujvo place structure.

In belenu-lujvo, the x2 (typically) of the tertanru is an event abstraction,
whose selbri is the seltanru, and whose internal sumti are the sumti of the
seltanru. This place in the tertanru is thus replaces by the places of the
seltanru bridi.

It cannot be stressed enough that this type of analysis, though it can be
made to apply naturally to many lujvo, is not appropriate for all of them.
Elimination of redundancies in lujvo not fulfilling these patterns has to
be done extemporaneously. Even with lujvo falling within these paradigms,
there are often extra redundant places that need to be eliminated.

Consider for example the lujvo {ninpe'i}, to newly meet, which has been
used to translate "to be introduced to". We can analyse this as a be-lujvo:
its GDS is {penmi be lo cnino}. The full GDS, though, is {da penmi de poi
ke'a cnino da kei di}. In other words, not only is c1=p2, but also c2=p1.
The lujvo place structure resulting should take advantage of this redundancy:
{da ninpe'i de di}, x1 is introduced to x2 (who is new to x1) at x3.

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non me tenent vincula, non me tenet clavis, % (nsn@munagin.ee.mu.oz.au)
quaero mei similes et adjungor pravis.      % Nick Nicholas, striver, EE&CS,
      --- Archipoeta, _Confessio_.          % Univ. of Melbourne, Australia