Lexical Semantics to Disambiguate Polysemous Phenomena of 
Japanese Adnominal Constituents 
Hitoshi Isahara and Kyoko Kanzaki 
Communications Research Laboratory 
588-2 Iwaoka, Iwaoka-cho, Nishi-ku 
Kobe, Hyogo, 651-2401, Japan 
{isahara, kanzaki}~crl.go.jp 
Abstract 
We exploit and extend the Generative Lexicon The- 
ory to develop a formal description of adnominal 
constituents in a lexicon which can deal with linguis- 
tic phenomena found in Japanese adnominal con- 
stituents. We classify the problematic behavior into 
"static disambiguation" and "dynamic disambigua- 
tion" tasks. Static disambiguation can be done using 
lexical information in a dictionary, whereas dynamic 
disambiguation requires inferences at the knowledge 
representation level. 
1 Introduction 
Natural language processing must disambiguate pol- 
ysemous constituents in the input sentences. A good 
description of information necessary for disambigua- 
tion in the lexicon is crucial in high quality NLP sys- 
tems. This paper discusses the treatment of linguis- 
tic phenomena in Japanese adnominM constituents 
and it focuses on how to generate the same semantic 
representation from different syntactic structures, 
and how to generate different semantic representa- 
tions from a semantically ambiguous sentence. We 
exploit and extend the Generative Lexicon Theory 
(Pustejovsky, 1995; Bouillon, 1996) to develop a for- 
mal description of adnominal constituents in a lexi- 
con which can offer a solution to these problems. 
We classify the problematic behavior of Japanese 
adnominal constituents into "static disambiguation" 
and "dynamic disambiguation" tasks. Whereas 
static disambiguation can be done using the lexical 
information in a dictionary, dynamic disambigua- 
tion needs inferences at the knowledge representa- 
tion level. This paper mainly discusses dynamic dis- 
ambiguation. 
2 Classification of the Usage of 
Japanese Adnominal Constituents 
On consideration of the syntactic relations between 
adnominal constituents and their head nouns, we 
find that some adnominal constituents can appear 
both in the attributive and predicative positions 
(Sakuma, 1967; Martin, 1975; Makino and Tsutsui, 
1986). However, some adjectives express different 
meanings when they appear in one or the other po- 
sition and some adjectives can appear only in one of 
these two positions (Hashimoto and Aoyama, 1992). 
We have classified the semantic relations between 
adnominal constituents and their modified nouns, 
based on whether the paraphrasing from attributive 
position to predicative position is possible or not. 
There are three possibilities: 
(Type A)A paraphrase can be made without 
changing the modifying relations semantically. 
Ad. + N -, N $~ (ga) Ad. (N is Ad.) 
Ad. = Adnominal constituent 
N = Head noun of noun phrase which 
is modified by Ad. 
(Type B) A paraphrase can be made only when a 
noun is restricted by its context: the presence 
of modifiers or determiners, e.g., articles. 
Ad. + N --* ~:¢)(sono) N F~ (wa) Ad. 
(that N is Ad.) 
(Type C) A paraphrase cannot be made at all, i.e., 
only the attributive position is available. 
Ad. + N --~ *none. 
We can classify semantic relations between ad- 
nominal constituents and their head nouns into three 
types by the use of paraphrase. Paraphrases exist for 
both Type A and Type B, however, a paraphrase 
cannot be made at all for Type C. This difference 
is based on the fact that adnominal constituents in 
types A and B modify the referents of their mod- 
ified nouns, while adnominal constituents in Type 
C do not modify their head nouns directly. Type 
C adnominal constituents modify (a) only a part of 
the meanings which their modified nouns allow, (b) 
the contents of the referents of their modified nouns, 
or (c) the states of being of the referents of their 
modified nouns. In this paper, we do not describe 
the semantic relations of (b) in detail but discuss 
489 
the semantic relations of (a) and (c) in the following 
section. 
There is a set of adnominal constituents which 
has the function of both adnominal and adverbial 
constituents (Teramura, 1991), and the third re- 
lation (c) above is the adverbial semantic relation 
which holds between adnominal constituents and 
their head nouns. 
3 Classification of Problematic 
Behavior of Japanese Adnominal 
Constituents 
It is important for the analysis of adjectives to con- 
sider what its head noun denotes in the sentence 
(Bouillon, 1996). Also, when we analyze word mean- 
ings, it is important to take both context and our 
world knowledge into account (Pustejovsky, 1995; 
Lascarides and Copestake, 1998). In this section, 
the behavior of Japanese adnominal constituents is 
classified into three types, depending on how the se- 
mantic representation of noun phrases is generated 
from information in the lexicon (Kanzaki and Isa- 
hara, 1997; Kanzaki and Isahara, 1998). 
The types are: (1) the type where one must infer 
the attribute of the modified noun which is expressed 
by the adnominal constituent, (2) the type which 
necessitates inferences that change the structures of 
the semantic representation, and (3) the type whose 
adnominal constituents do not add information to 
the modified nouns but constrain the relations be- 
tween constituents in the text. These types are ex- 
plained in this section. Both semantic types A and 
B correspond to syntactic types 1 and 2. Type C 
corresponds to type 3. 
3.1 Adnominal Constituents that Express 
the Attributes of the Modified Noun 
\[Static disambiguation\] 
This is the case where an adnominal constituent 
modifies a head noun semantically. Adnominal con- 
stituents modify nominals syntactically and most of 
these modify their head nouns semantically. Here, 
the "analysis" of the relationship between adnomi- 
nal constituents and their head nouns concerns the 
choice of the particular attribute of the nouns which 
adnominal constituents modify. There are two types 
of inferences for disambiguation. 
3.1.1 Adnominal Constituents that Express 
Unique Inherent Attributes of the 
Modified Noun 
This is the case in which the relation between the 
adnominM constituent and its modified noun, i.e., 
what slot of the modified noun the modifier fills, can 
be predicted. 
In Example 1, F@$~P~Tk (yuruyaka_na, gen- 
tle)_l is the attribute value of an instance of the 
concept I-~ t (keisha, slope)J . The instance \[-{~ 
~r (keisha, slope)J involves a unique inherent at- 
tribute, i.e., "the angle (degree) of the slope," there- 
fore r@~-~,~ (yuruyaka_na, gentle)J is taken 
to be a value on the scale of the slope. The noun in 
this example has a unique inherent attribute whose 
value is number or intensity. 
Example 1 
yuruyaka_na keisha , 
gentle slope 
Japanese pronunciation 
literal translation 
3.1.2 
KEISHA (slope) YURUYAKA_NA (gentle) \]degree I 
Adnominal Constituents that Express 
One of the Major Attributes of the 
Modified Noun 
This is the case in which the NLP system must iden- 
tify the slot of the modified noun which is filled by 
the modifier. Most nouns do not have a unique 
inherent attribute but have several attributes that 
adnominal constituents may embody. In Example 
2, \[-:~1 (otoko, man)J has several major attributes, 
e.g., name, age, character, and physique. An un- 
derstanding system must choose a suitable attribute 
(i.e., physique in this example) to plug information 
in from these attributes. 
Example 2 
oogara_na 
large 
otoko 
man 
OTOKO (man) ~,~ 
age \[ I"- OOGARA_NA (large) name I ' ~._1" 
physique/ vJ , character ~ \[ \] 
These types of adjectives can appear both in the 
predicative position and in the attributive position 
without changing their meanings (Sakuma, 1967; 
Teramura, 1991; Hashimoto and Aoyama, 1992). 
r:gk:~: (oogara_na, large)J in Example 2 can ap- 
pear in predicative position, i.e., I-~:¢)~IJ~Jk:~ 
(sono otoko wa oogara_da, that man is large)_l , with 
the same meaning that the man has a big physique. 
We cannot decide on one particular attribute of 
the head noun without suitable semantic informa- 
tion. Also, still another problem remains here, that 
490 
is to identify whether the sentence needs a generic 
reading or whether it represents an instance of the 
concept. 
3.2 Adnominal Constituents that Express 
Attributes of the Situation Inferred 
from the Modified Noun \[Dynamic 
disambiguation 1\] 
In some cases, adnominal constituents do not modify 
instances of nouns themselves, but modify, instead, 
instances of events, situations, or knowledge that are 
inferred from (the context of) the modified noun. 
3.2.1 The Case in which New Elements 
must be Infered in the Semantic 
Representation 
There are cases in which we have to infer new ele- 
ments in the semantic representation so as to rep- 
resent semantic relations between adnominal con- 
stituents and their modified nouns. 
In Example 3, the adjective modifies some event 
participated in by the household members. A house 
cannot have a temporal scale as an attribute, how- 
ever, an event, in this example, spring-cleaning, can 
be inferred from the context and therefore the ad- 
jective F~w (hayai, early)J can modify the event, 
e.g., the beginning time of spring-cleaning. 
However, its computational implementation is not 
so simple, because there are metonymic extensions 
going on in this example. For example, even if an 
NLP system can find "spring-cleaning" in the con- 
text as an event whose "begining-time" is "early," 
the system must infer the people living there from 
"house" and identify him/her as an agent of the 
spring-cleaning. 
Some of these inferences are done using syntactic 
structure in English, however , that is not possible in 
Japanese. Such metonymic extensions are essential 
for determining the nature of the modifier/modified 
relationships in Japanese (Matsumoto, 1993). 
Example 3 
(oosoji_no) hayai ie 
(spring-cleaning) early house 
"The house whose member begins spring-cleaning 
early." 
OOSOJI HAYAI (early) (spring-cleanin~) , \[ 
I beginning-time --------~ 
- II 'HITO(  on) 
IE (house) I 
\]member \] ..--1 
3.2.2 The Case in which a Concept must 
be Converted into a Set of Concepts 
Adnominal constituents sometimes do not modify 
nouns as a whole but modify only specific features of 
a noun. Example 4 is ambiguous. The "as a whole" 
interpretation is that this person likes something and 
he/she is abnormal as a whole, i.e., this person has 
some mental disorder. The "specific" interpretation 
is that this person likes something abnormally, i.e., 
the way this person likes something is abnormal, i.e., 
this person is crazy about something x. Ambiguities 
of \['~,~ (ijo_na, abnormal)_l in Example 4 will 
be discussed systematically below. 
Example 4 
ijo_na sensei-jutsu_no aikosha 
abnormal astrology enthusiast, one who 
likes something very 
much 
As a whole interpretation 
IJO AIKOSHA SENSEI-JUTSU 
abnormal) (enthusiast) (astrology) I 
Specific interpretation 
IJO AIKO-SURU SENSEI-JUTSU (abnormal) (like) (astrology) 
object object ~ \[ 
To treat the "specific" interpretation, the system 
has to perform the concept conversion (Isahara and 
Uchida, 1995) shown in Figure 1. 
As for the "as a whole" interpretation, an adnomi- 
nal constituent modifies an extension of the modifiee 
(e.g., what is abnormal is a person who is an astrol- 
ogy enthusiast). Therefore, the object slot of (an 
instance of) "abnormal" is filled by (an instance of) 
"enthusiast." In the "specific" interpretation, how- 
ever, an adnominal constituent modifies part of the 
intensions to which the modifiee refers (e.g., what is 
abnormal is the way that person likes something). 
An analysis module converts the semantic structure 
(Figure 1) and the object slot of (an instance of) 
"abnormal" is filled by (an instance of) "like" which 
is extracted by the concept conversion. 
1There is one more interpretation that "an enthusiast who 
likes abnormal astrology," however, this interpretation is odd 
in this example. 
491 
AIKOSHA (enthusiast) something 
Concept Conversion 
AIKO-SURU like) something 
object~ 'l agent----\[-\] \[ \] 
~HITO (perTn) 
"enthusiast" J 
Figure 1: Concept Conversion 
The concept conversion is, in a sense, a paraphrase 
of the original expression. The concept conversion 
is also useful in analyzing Example 5. 
Example 5 
sensei-jutsu_no ijo_na aikosha 
astrology abnormal enthusiast 
Example 5 is not ambiguous, i.e., the only inter- 
pretation is % person who likes astrology abnor- 
mally," because the "as a whole" interpretation is 
not possible. Example 5 can be paraphrased into 
the phrase shown in Example 6. If I-~ (sensei- 
jutsu, astrology)A is semantically an object of r~ 
~-"f B (aiko_suru, like)A, r~$~c (ijo_ni, abnor- 
mally)2 cannot modify r~ (mono, person)J , be- 
cause the dependencies in this interpretation cross 
each other. 
Example 6 
sensei-julsu_wo ijo_ni aiko_suru mono 
astrology abnormally like person 
Example 7 exhibits the adnominal constituent 
F~?~ (ijo, abnormal)J in a predicative position. 
Using the extension of the Late Closure strategy 
(Frazier, 1979), only the "as a whole" interpretation 
is possible. 
Example 7 
aikosha_ga ijo_da 
enthusiast abnormal 
"The enthusiast is abnormal." 
3.3 Adnominal Constituents that Constrain 
the Relations between Constituents in 
the Text \[Dynamic disambiguation 2\] 
3.3.1 Adnominal Constituents that do not 
Add Information to their Modified 
Nouns Directly 
Adnominal constituents mostly modify nouns syn- 
tactically and also semantically. However, some 
adnominal constituents work differently, i.e., they 
modify nouns syntactically but not semantically. 
Japanese nominal adjectivals F~: (junsui_na, 
pure)A, F~.~::~: (kanzen_na, perfect/complete).\] 
and \[-:~ < (mattaku, entire).\] are typical examples 
of this type. 
1-i~4~ (junsui_na, pure)A in Examples 8-10 and 
\[-~.~: (kanzen_na, complete)_l in Examples 11-13 
play different semantic roles. 
Example 8 
junsui_na 
pure 
"pure water" 
Example 9 
t~at 
ekkyo_wa 
border 
transgression 
mizu 
water 
junsui_na seiji_bomei datta. 
pure political (copula, 
flight past) 
"The border transgression was a pure political 
flight." 
Example 10 
junsui_na churitsu_wa mutsukashii. 
pure/strict neutrality difficult 
"Strict neutrality is difficult." 
Example 11 
kanzen_na shisutemu dewa nai. 
complete system (copula) (negation) 
"This is not a complete (perfect) system." 
Example 12 
nousakumotsu_wa kanzen_na syohizai dearu. 
farm products complete consumer (copula) 
products 
"Farm products are nothing but consumer 
products." 
Example 13 
kanzen_na mujin_no yakala 
complete uninhabited house 
"absolutely uninhabited house" 
492 
In Example 8, Fi~ (junsuLna, pure)J de- 
scribes the purity of water, i.e., it describes some- 
thing within the "water" concept. The adnominal 
constituent I-gk:~Tz (oogara_na, large)J , in Exam- 
ple 2, expresses a value of an attribute of the modi- 
fiednoun, i.e., \[-~ (oloko, man)J . In contrast, the 
adnominal constituent \[-~ (junsui_na, pure)J , 
in Example 8, does not express a value of an at- 
tribute of the modified noun, i.e., FT\]( (raizu, wa- 
ter)\] , but expresses the way some values fill at- 
tributes of this modified noun. That is "nothing but 
water is a filler of an attribute of the referent." In 
Example 11, F-~_/k (kanzen_na, complete)\] de- 
scribes the completeness of a system as well, i.e., 
it describes something within the "system" concept, 
e.g., the function of the system. (Case 1) 
In Example 9, Fi~ (junsuLna, pure).l does 
not add information as to the purity of this polit- 
ical flight, however, it describes that there is only 
one purpose (or motivation), i.e., political flight, for 
this "border transgression." In other words, there is 
no other motivation, such as sightseeing or economic 
reasons, which would explain this action. {-~,~: 
(junsui_na, pure)J describes something outside of 
the "political flight" concept. In Example 12, r~ 
:~.~ (kanzen_na, complete)J plays a very similar 
role to that in Example 9. It notes that there is 
only one purpose, i.e., consumer products, which 
describes "farm products." In other words, there 
are no other usages, such as raw materials, for these 
products. (Case 2) 
Both referents in Examples 8 and 9 are still "wa- 
ter" or "political flight" even if they are not "pure," 
however, Example 10 means that strict neutrality is 
difficult, and "not pure" neutrality is not a neutral- 
ity in the strict sense of the word. \['~4~ (jnn- 
suLna, pure)3 describes the concept "neutrality" 
itself. As for Example 13, "not absolutely" unin- 
habited is not uninhabited in the strict sense of the 
word, as well. (Case 3) 
There are similar phenomena involving many 
other adnominal constituents in Japanese. Formal 
treatment of these phenomena will be discussed in 
Section 4.1. 
3.3.2 Adnominal Constituents which 
Represents a State of Being 
Some adnominal constituents, e.g., F:~/:~ 
(rippa_na, splendid)\] can be used in attributive po- 
sition so as to express the state of the modified noun. 
In Example 14, the adnominal constituent \[-3~ 
(rippa_na, splendid)J does not describe aspects 
of an island itself, but the nature of what is required 
for it to be considered an island. In other words 
"this really is an island, not a large rock." 
Example 14 
rippa_na sh~ma 
(splendid) (island) 
"Once this ocean mountain is elevated, or as 
we described above, its top appears above the 
ocean from the sea level falling, it will be a 
real island." 
Whereas adnominal constituents in Examples 8 
and 11 can appear both in the attributive posi- 
tion and in the predicative position without chang- 
ing their meanings, and Examples 9, 10, 12 and 
13 cannot appear in the predicative position with- 
out changing their meanings, when this F~& 
(rippa_na, splendid)J occurs in a predicative posi- 
tion, i.e., F~h~ "¢t:_~7~ (shima ga rippa_da)J, it 
means that "the island is splendid," a state of the 
island s . 
As \[--0:~ (rippa_na, splendid) ~ (shima, is- 
land)J without context has two interpretations, i.e., 
describing aspects of an island itself, "the island is 
splendid," and describing the nature of what is re- 
quired for it to be considered an island, when an 
NLP system analyzes this noun phrase, the system 
has to choose a suitable interpretation from these 
two possibilities in the context of the semantic re- 
lations between adnominal constituents and their 
modified nouns. Furthermore, in order to inter- 
pret the semantic relations between adnominal con- 
stituents and their modified nouns, it is sometimes 
necessary to infer instances of newly introduced con- 
cepts using both contextual and world knowledge. 
Example 3, I--~ (hayai, early) ~ (ie, house)_\] , 
in Section 2.2.I illustrates this. It is important for 
a lexical semantic system to take both context and 
our world knowledge into account. We should ana- 
lyze semantic functions of lexical items from several 
points of View. 
4 Formal Treatment of Problematic 
Phenomena of Japanese 
Adnominal Constituents 
In this section we discuss the formal treatment of the 
phenomena described in Section 3.3.1, i.e., Cases 1, 
2 and 3. 
4.1 Hypothesis and Definition 
To handle these phenomena, we have established the 
following hypothesis and definition. 
2 "Real" is a similar example in English. "A real friend" 
means "true friend" and "His friend is real" means "his friend 
is not imaginary." 
493 
\[HYPOTHESIS\] 
(a) There is something which can be shared by 
a plural number of constituents, e.g., there 
is some semantic definition which can con- 
tain/represent/embody/refer to various items. 
(b) Fi~IC~Z (junsui_na, pure)J works to constrain 
this number to one. 
Extending the Generative Lexicon format, some- 
thing pure is represented as 
Az\[stg(x) A Telic = !1 Ae\[~oa,~ob, ~c,...\]\] 
Here, '!1' is a function which restricts the number of 
its element to one. 
\[DEFINITION\] 
F~Z Uunsui_na, pure)3 is represented as 
pure ~ ASemN.ANewArg.\[p(SemN, NewArg)\] 
(1) 
Here, SemN and NewArg are underspecified types. 
In syntax, an adnominal constituent takes a noun 
as a syntactic argument and returns the same syn- 
tactic category (i.e., a noun). Semantically, it takes 
the semantics of the noun first, and returns the se- 
mantics of a one-place function, that is it narrows 
the semantic definition of the noun. 
Starting from (1), suppose we define 'p' as follows: 
Case 1 (SemN is constitutive/mass material 
therefore NewArg is too.): 
p ~ Vy.\[~(SemN(y)) --~ ~(y E NewArg)\] 
This is logically equivalent to the following: 
p ~ ~3y.\[~(SemN(y)) A (y e UewArg)\] 
(3) 
In Example 8, Fi~: Ounsui_na, pure) ;t~ 
(mizu, water)J , SemN is water and NewArg 
is some liquid referred to by this example sen- 
tence. That is "anything that is not water does 
not exist in this liquid." 
Case 2 (SemN is individual entity/event.): 
p VU.\[- (u=SemN) 
--~ ~(view( NewArg, y))\] 
(4) 
In Example 9, Fi~i~#-J: (ekkyo_wa, border 
transgression) ~ (junsui_na, pure) ~'~I:~ 
(seiji_bomei, political flight) f~-9 f~o ( datta, 
(copula, past))3 , SemN is "a political flight." 
The sentence refers to the fact that "the border 
transgression is a pure political flight." Thus, it 
is associated with the interpretation of NewArg, 
that is there is only one view of this action (bor- 
der transgression), i.e., "political flight." 
It seems that the semantics of "pure" shares the 
basic logical structure as seen in (2), (4), however, 
case 3 requires a different treatment. 
Case 3 (SemN is predicate/state.): If SernN is a 
predicate/state P, NewArg is generated as a 
sortal array of P and ~P. The binary predi- 
cate is coerced into a polar predicate. 
As for Example 10, neutrality is originally a bi- 
nary sortal predicate, that is 
VP\[neutrality(P) V neutrality(~P)\]. 
In this case, neutrality is coerced into two polar 
predicates, i.e., c~ which denotes "strictly neu- 
tral" and/3 which denotes "strictly not neutral." 
'~ a' and '~ fl' denote "not strictly" neutral, 
or a range of situation which can be considered 
as neutral. 
4.2 Adnorninal Constituents and Adverbial 
Constituents 
Japanese nominal adjectivals, such as F~ (junsui, 
pure)_l , are inflected as follows 3. 
F~(2~CZ (junsui_na, pure)J , adnominal 
FEW- OunsuLni, purely)_l , adverbial 
F~2~ (junsuLsa, purity)J < nominal 
The nominal adjectival Fi~d~ (junsui, pure(ly))J 
modifies Fi~g::~ (seiji-bomei, political flight)J 
syntactically in Example 15 (adnominal) and mod- 
ifies Ffg-gfc (datla, (copula, past))J syntactically 
in Example 16 (adverbial). These two sentences have 
different syntactic structures, however, they have al- 
most the same meaning 4. Descriptions in a lexi- 
con of nominal adjectivals, such as F~I~ (junsui, 
3These expressions belong to the same syntactic category, 
nominal adjectival. In English, on the contrary, the adnomi- 
hal constituent "pure" is an adjective and the adverbial con- 
stituent '~purely" is an adverb. 
4Readers might think that the Japanese copula in gen- 
eral syntactically takes a noun and returns some kind of verb 
phrase. Then, as in the ease of the English copula, the se- 
mantics of the Japanese copula is "transparent." Thus, the 
function of 'tpure" taking either the adnominal or the adver- 
bial form should apply to the semantics of the common noun, 
494 
pure(ly))J , must be able to explain this kind of lin- 
guistic phenomena. 
Example 15 
junsui_na seiji-bomei dalta. 
pure political flight (copula, past) 
Example 16 
~ ~ ~ ~ ~o 
junsui_ni seiji-bomei datta. 
purely political flight (copula, past) 
Example 17 
~ ~ "~ ~ o 
sezjimbomei da~ta. 
political flight (copula, past) 
A nominal refers to an extension of a thing with 
one or several intension(s). A copula refers to an in- 
stance of a state, which is a subconcept of an event. 
This state also has one or several extension(s) of 
events. The meanings of Examples 15, 16 and 17 
are a function (or mapping) from extensions, i.e., 
"the border transgression," to intensions, i.e., "al- 
ternative views about a certain event." Then, Ex- 
ample 17, "the border transgression was a political 
flight" without "pure," corresponds to alternative 
views about "the border transgression," where the 
particular view as "political flight" is positively as- 
serted and others are left unstipulated. Then, Ex- 
ample 17 can be represented as follows; 
statel(views 
= extensionl(views = political flight, 
intensionl2, ...) 
extension2(views = intension21, 
intension22, ...) 
extension3(views = intension31, 
intension32, ...) 
...) 
I'~ (junsui, pure(ly))3 in its adnominal usage 
(Example 15) corresponds to the views of an exten- 
sion and constrains the number of intensions to one 
by using the function '!1' introduced in Section 4.1 
as shown in the following; 
which is indistinguishable from other one-place verbs. How- 
ever, some Japanese adjectives, e.g., r~,~ (akai, red)2 can 
be used only as an adnominal constituent. ~,w (akai, 
red (adnominal)) ~ (hako, box) E (da, (copula)) 
*~< (akaku, red (adverbial)) ~i (hako, box) E (da, (copula)) 
The copula in Examples 15-17 has a meaning similar to the 
verb "exist," therefore, it is not "transparent." Thus, it is 
necessary to analyze each of these sentences differently as we 
would sentences with ordinary verbs. 
extensionl(views = intensionl, 
intension2, 
extensionl(views = intensionl) 
...) 
Then Example 15 is represented as follows; 
statel(views 
= extensionl(views = political flight) 
extension2(views = intension21, 
intension22 .... ) 
extension3(views = intension31, 
intension32 .... ) 
...) 
\['i~ (junsui, pure(ly))_l in its adverbial usage 
(Example 16) corresponds to a state and singles out 
one extension using the function '! 1' as the following 
shows; 
statel(views = extensionl, 
extension2, ...) 
statel(views = extensionl) 
Then Example 16 is represented as follows; 
statel (views 
= extensionl(views = political flight, 
int ension21 .... ) ) 
Strictly speaking, these three example sentences 
represent different meanings. However, one tends to 
take no notice of this difference in daily conversation. 
Here, we introduce a new hypothesis to explain 
the similarity of these representations. 
\[HYPOTHESIS\] 
Extensions and intensions which are not men- 
tioned by overt expressions are not stressed in the 
context. They contribute little to the interpretation 
of a sentence. 
Therefore, Examples 15, 16 and 17 can be repre- 
sented similarly as follows; 
statel(views 
= extensionl(views = political flight)) 
The above simplification for Example 17 was all 
done following the above hypothesis, however, parts 
of the simplifications for Example 15 and 16 were de- 
pendent on the presence of "pure." Therefore, the 
reliability of these simplifications is different. To dis- 
cuss this interesting fact further is, however, beyond 
the scope of this paper. 
495 
5 Conclusion 
This paper discussed the treatment of linguistic phe- 
nomena in Japanese adnominal constituents and it 
focused on how to generate the same semantic rep- 
resentation from different syntactic structures, and 
how to generate different semantic representations 
from a semantically ambiguous sentence. 
In this paper, we classified the characteristics of 
adnominal constituents. That is (1) the type where 
one must infer what attribute of the modified noun 
is expressed by adnominal constituents, (2) the type 
necessitates inferences that change the structures of 
semantic representation, and (3) the type where the 
adnominal constituents do not add information to 
their modified nouns but constrain the relations be- 
tween constituents in the text. 
To achieve good results in natural language pro- 
cessing, e.g., high-quality machine translation, we 
have to consult lexicons based on concepts and so 
we exploited a concept representation method based 
on the Generative Lexicon Theory and a concept 
conversion module. Using these techniques, we ex- 
plained how the semantic ambiguities of adnominal 
constituents can be dealt with by analyzing the mod- 
ification relations between adnominal constituents 
and their modified nouns. 
For a more precise explanation of adnominal ex- 
pressions within our framework, it would be neces- 
sary to treat (1) the scope of negation, (2) negation 
and position of adnominal constituents, i.e., attribu- 
tive and predicative position, and (3) disambigua- 
tion with regard to the context and the position of 
adnominal constituents. 

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