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<Paper uid="C88-2110">
  <Title>On The Semantic Interpretation of Nominals</Title>
  <Section position="2" start_page="0" end_page="520" type="intro">
    <SectionTitle>
1. Introduction
</SectionTitle>
    <Paragraph position="0"> Much of the work on polysemy has tended to confuse the nature of word meaning by labeling many different types of ambiguity as the same phenomenon. In the extreme case, every possible lexieai semantic distinction is a case of polysemy and must have its own conceptual representation. In such a theory, various features are introduced to distinguish one sense from another~ but the meanings m'e all part of the same homogeneous conceptual space.</Paragraph>
    <Paragraph position="1"> In this paper, we argue that there are various types of polysemy, some more accessible to grammatical phenomena than others. We use this as a principled distinguishing characteristic of polysemous types. We distinguish two systems that together comprise the meaning of lexieal items, the lexical system and the conceptual system. In particular, if there are certai n grammatical characteri,~tics that are affected by a polysenmus relation between concepts, then we will say that this relation is overtly part of the lexical  anick@aiag, dee @decwrl. dec. corn and</Paragraph>
    <Section position="1" start_page="0" end_page="0" type="sub_section">
      <SectionTitle>
Computer Science Department
Brandeis University
</SectionTitle>
      <Paragraph position="0"> system. 1 The mQor point to be argued here is that polysemy is not a. single phenomenon operating over all lexical items with equM force and frequency. Rather, Lhere are subsystems in the lexicon which exhibit a restricted range of polysemous behavior. Each subsystem is determined by a representation called a Lexieal Conceptual Paradigm (LCP), which groups elements into classes with similar behavior. We limit ourselves in this paper to cases of polysemy involving nominals.</Paragraph>
      <Paragraph position="1"> We will proceed as follows. In Section Two we examine the different types of polysemous nominals. In particular, we look at a classification of relational nouns, paying particular attention to those exhibiting polysemous behavior. Then we examine the semantic interpretations possible for artifactual nominals such as book and record, and their associated polysemous behavior resulting from certain syntactic contexts. In Section Three we introduce a framework ibr representing this information in the lexicon. We argue that certain semantic information associated with nomina~ is more priviliged and accessible to syntactic selection than other knowledge associated with the word. We term these privileged properties the hidden-event roles of a nominal, and they form part of the Lexical System of semantic analysis. All other information forms part of the more traditional notion of a conceptual space, what we term simply the Conceptual System. Finally, in Section Foul&amp;quot; we look at the computational implications of 1 We will discuss neither lexical ambiguity for verb~ trot holnonymy. Our poinL here is to narrow iwl on the finer sel~antic distinctions within a smaller set of lexica\] items. For general discussion on iauues in lexical ambiguity, however, see /Boguraev 1979/, \]Hit~t 1987/,/H~we~ 1977/, and/Wilks 1975\]'. See/StMlard 1987/for a related approach to polyaemy.</Paragraph>
      <Paragraph position="2"> 2 As this group of nominals has been ~tudied extensively in the linguiBtic literature (cf. for example, /Anderson 1979/, /Puatejovsky 1984/, /Willimm~ 1985/, /Saflr 1987/, /Moor$gat 1985/), we will diecuss it here only briefly, suc~h a lexic:d organization. The distinction is an important one for computational reasons. First, it establishes clear criteria for partitioning the semantic information associated with a word; this will bear directly on the decisions made by a parser in order to disambiguate lexical items during a parse. Secondly, it affects the planning strategies necessm3r for lexicM selection in the process of language generation. Finally, it relates to the question of how to enter multiple word senses for a lexical item. According to this view, those words containing logical ambiguities carry these sensc.,~ in the same entry.</Paragraph>
      <Paragraph position="3"> 2. The litelational Structure of Nominals One reason to studythe semantics of relational nominals is that they exhibit polysemy in very well-defined and structured ways. For example, nominalizations such as arrival, destruction, and solution are ambiguons between the event aorniltal reading and the resultative reading, as illustrated in (1) through (3)Y  (1) a. We witnessed the city's destruction. Event b. The destruction was widespread throughout the city. Resnltative (2) a. Mary's arriva ! is expected to be at 3:00 pm.</Paragraph>
      <Paragraph position="4"> Event b. Mary's arrival means that she gets the couch.</Paragraph>
      <Paragraph position="5"> Res~tltative (3) a. John's solution to the problem took 20 minutes.</Paragraph>
    </Section>
    <Section position="2" start_page="0" end_page="520" type="sub_section">
      <SectionTitle>
Event
</SectionTitle>
      <Paragraph position="0"> b. This solution is too difficult to understand. Resultative null It seems natural to ascribe the relational senses to nominalizations ;~s being some projection of their related verbal argument si;ructure. There axe many nominals, however, which are oot nominalizations, yet seem to refer to relations in their meaning. Classic examples include nouns such as picture and story, a The difference is that their relational structures are implicit, while the relation in a nomhtalization is explicit.</Paragraph>
      <Paragraph position="1"> Let us now turn to the class of dependent nominals. If the denotation of one sense of a lexical item is &amp;quot;depende:ct&amp;quot; on another, then that dependency is part of the semantic representation of that lexical item. A familiar example is father or mother, where the relational nature 'must be p~xt of the semmatics of the noun. 4 We term these Primitive relational nominals. Perhaps not as familiar are nouns such as blemish, wart, scratch, cut, etc. In each of thesd cases, the object is evaluated with respect to another object, and in fact it is hard to imagine the dependent object existing in isolation. For this reason, these will be called Primitive Figure-Ground nominals. The object itself is the figure to a necessary ground object.</Paragraph>
      <Paragraph position="2"> A related class of lexical items includes nouns such as window and door. These are not simply Primitive Figure-Ground nominals, for notice that there is a hidden argu- null ment present that relational nouns such as wart do not have.</Paragraph>
      <Paragraph position="3"> (4) a. Plastic windows are on sale at Lechmere.</Paragraph>
      <Paragraph position="4"> b. The cat crawled through the window.</Paragraph>
      <Paragraph position="5"> (5) a. John painted the door blue.</Paragraph>
      <Paragraph position="6"> b. John walked through the door quickly.</Paragraph>
      <Paragraph position="7">  As pointed out in \]Lakoff 1987/, as well as/Talmy 1975/, the nouns here are polysemous, since the window referred to can be the opening as well as the object. Thus, the hidk. den argument mentioned is the open space that is left as a result of the absence of the window. We term this argument the inverted figure, and the noun class itself Double Figure-Ground Nominals. 5 In Section Three, it will bc shown that the polysemy illustrated in (4) and (5) is very different from word senses not making reference to either the figure or inverted figure.</Paragraph>
      <Paragraph position="8"> The next class of relational nominals are those which enter into a specified relation; namely, the class of artifacts. An artifact is, by definition, an object associated with a particular activity or event; for example, cigarettes are for smoking, books are for reading, etc. Because of these associated activities, this class of nouns exhibit polysemous  behavior.</Paragraph>
      <Paragraph position="9"> (6) a. This record weighs an ounce.</Paragraph>
      <Paragraph position="10"> b. This record lasts 35 minutes.</Paragraph>
      <Paragraph position="11"> (7) a. The book has a red cover.</Paragraph>
      <Paragraph position="12"> b. This book will talCe a week (to read).</Paragraph>
      <Paragraph position="13"> (8) a. These cigarettes are longer thaal the normal size. b. His cigarette is bothering me.</Paragraph>
      <Paragraph position="14"> 3 See /Pustejovsky 1984/, /Safir 1987/, and /WilliamB 1985/ for further discu6slon. null 4 /Partee and Kamp 1986/discusses the semantics of such nominals. 5 Another type of dependent nomilml is that seen with 'lock ~ and ~key'. These objects do exi.t independent of the ground object it is associated with through its  function, but still allow selection for this dependency; for example, &amp;quot;key to the lock&amp;quot; and &amp;quot;10ck for the door&amp;quot;.</Paragraph>
      <Paragraph position="15">  The polysemy in (6) arises becmme of the possible reference to the event of playing the record as well as the record by itself. Similarly, in (7) the book itself or the event of reading the book can be referred to by the nominal. Finally, the difference in (8) points to the cigarette as an object with attributes versus an object in the context of being smoked. ~ In this section we have presented five types of relational nominals (nominalizations, primitive relationals, primitive figure-grounds, double figure-grounds, and artifactual nominals), showing how they exhibit subtle but productive polysemous behavior. In the next section, we outline our approach to polysemy and preserit an explanation of these lexieal mnbiguities in terms of a richer semam  tic representation.</Paragraph>
      <Paragraph position="16"> 3. The Theory of Lexical Organization  Unlike many previous approaches to word meaning, we distinguish the logical lexieal semantics of a word from its deeper, conceptual denotation. .t We term these the L-system and U-system, respectively.</Paragraph>
      <Paragraph position="17"> The L-system is the particuhu- organization that the lexicon assumes independently of the conceptual system. Only semantic information tlmt is somehow reflected in the syntax is represented here.</Paragraph>
      <Paragraph position="18"> The C-system is the organization of the concepts themselves and not the language. This is the structure of the me~mings, and as such, would be represented as a semantic network or radial category structures (Cf./Hayes 1977/,/Lakoff 1987/).</Paragraph>
      <Paragraph position="19"> l)br each of the nominal types described in the previous sections, we give lexical representations which allow us to capture their polysemous behavior. Consider first the Double Figure-Ground Nominals in (4) and (5). The lexical semantics of such nouns as window and door must refer t,o the three arguments mentioned by the implicit relation, the figure, ground, and inverted-figure. Assuming a first-order, partial-decomposition model of lexical semantics, as given in /Pustejovsky 1987/, the translations for this class would be as follows: 6 It should be pointed out here that these are not case~ of metonymy. In metonymy, the ability of one referring expression to stand in for another object is very uneonstrained~ and fails to conform to any strict 9ondiLiolm on flllblltitutioIl t unlike t|le ea~ea mentioned above,  (10) doo,. =. ~,~y\[~,.ti/~(~) ^ Vig.,.4~) ^ G,'o~-,4c) A rig~,.~,(y) ^ ~(~, go.tl,...(~, y))\].</Paragraph>
      <Paragraph position="20">  where the three.-place relation is explicitly represented as a conjunction of functions over the argmnents~ c is a co,_~stant~ Figurei is the inverted-figure, and ~, is a metalogical operator indicating the purpose of the object being defined (el. /Pustejovsky in '1,reparation~). The important thixa5 to note about this representation is that it predicates two distinct types of information over two different but rein,ted arguments, x and y; inanely, that a door~ for example 4 is defined in terms of both the concrete object whi(:h is arti-Net (the figure), and the space in the absence of this object (the inverted-figure). Thus, differeiit matrix predications will foreground different subexpressions in the semantics ibr the norm. For example, in (Sa), the artifact reading is selected, picking out the figure, while in (5b) the inverted-figure is selected.</Paragraph>
      <Paragraph position="21"> (5) a. John painted the door blue.</Paragraph>
      <Paragraph position="22"> b. John walked through the doo'r quickly.</Paragraph>
      <Paragraph position="23"> We argue that these are the only two types of polysemy tbr these nominals that are lexieally motivated, and that o~her apparent eases of polysemy are .simply inferences associated with the conceptual representation of the object. This can be seen in sentence such as (1l), taken from /Lakoff 1987/.</Paragraph>
      <Paragraph position="24"> (11) a. The window is rotting. (Reference to the wood) b. The kids broke the window. (Ii.eibrenee to the pane) These are not reMly polysemous in our sense, since the argument structure of the verb selecting the nominal does not specify how the noun is to be interpreted. That is, although both readings select for the ~u'tifact interpretatlon, only inferences in the conceptual system, and not the lexieal semantics, tells us that rotting is predic~ted of tlhe wooden part of the window, s Another importmlt aspect to the representations in (9) m~d (10) is the expression introduced by the operator ~r. '\['his is an exmnple of a hidden-event 'role denoted by a nominal expressiom I a the case of door, the hiddcn-evex_,t ............. -8--~;\/ie~tructure of ~he conceptual ~ya~em will permit such infvx'cnce~ in a nutm,al wetv, depending on the eyatem'~ colamon~len~e model of physics ~xnd agaric0, gee, /Hobbs et al 1986/for aL mlggeative ~pl)rot~eh to such i~auea. is go.through(w, y), a pointer to a particular lexical item, its argumelg; structure, and its selectional properties.</Paragraph>
      <Paragraph position="25"> The richer representations in (9) and (10) now prorides us ~vith a mechanism for capturing some interesting and subtle lexical distinctions in the artifact nominal class. For nouns such as record, book, and bulb, we assign the following semantics: 9  (12) record .=~ ~z3e\[arti/aet(x) ^ 7r(x, play(e,z))\]. 1deg (13) book=c. ,\x3e\[artifact(x) A r(x, read(e,w, x))\].</Paragraph>
      <Paragraph position="26"> (14) bulb ~ ~x3e\[arti/aet(z) A ~r(x,illuminate(e,z))\]. By explicitly referencing the event that the object is associated wiLh we can solve several puzzles. First, notice that when the event readings of record and book are selected, they differ in their aspectual interpretations.</Paragraph>
      <Paragraph position="27"> (15) a. This record lasts 35 mimttes.</Paragraph>
      <Paragraph position="28"> b. This book takes a week (to read).</Paragraph>
      <Paragraph position="29"> c. *This record takes 35 minntes.</Paragraph>
      <Paragraph position="30"> d. ?This book lasts a week.</Paragraph>
      <Paragraph position="31">  This is certainly surprising if no reference is made to the type of egent referenced by the object. Within the calculus of aspect outlined in/Pustejovsky 1987/, play(z) and read(x,y) fall into different event-types, activity and ac.complishment, respectively, and license different temporal predicates. So, it is not surprising that lexical semantic information is accessible to such processes in the grammar. Another interesting application of the notion of hidden event (or h-event) comes from evaluative predicates. 11 \])'or example, consider the differences between the (a) and  (b) NPs below: (16) a. a vinyl record: ~P3x3e\[arti/aet(x) A vinyl(x) A ~(~,playCe,~)) ^ P(z)\].</Paragraph>
      <Paragraph position="32"> b. ~ long record )tP3x3e\[arti/aet(x) A r~(x,play(e,x)) A Ion.~(~) ^ P(x)\].</Paragraph>
      <Paragraph position="33"> (17) a. an opaque bulb ~P3x3e\[arti/act(z) A opaque(z) h</Paragraph>
      <Paragraph position="35"> In (16b), long is a property that only the playing of the record has, while in (17b), bright is a property that only the state of illumination for bulbs has (el. /Jackendoff 1983/for multiple senses of lexical items). By adopting a semantics that makes reference to events, just as with nominalization:b 12 we can begin to understand how to analyze evaluative predicates. Nmnely, in the cases above, we can distinguish the types of attribution as predication over an individual variable, the artifact ((16a) and (17a)), or over an event variable, the hidden event ((165) and (175)).</Paragraph>
      <Paragraph position="36"> The structures given in (12)-(14) are all examples of artifactual objects. The general abstraction for these individuals is the concept of an object made for a particular use: ,\x3e\[arlifaet(x) A lr(x,~\[e,x\])\] where c~ is some predicate. Such a structure we will term a Lexical Conceptual Paradigm (LCP). We view these nominals as exhibiting paradigmatic behavior (much like the inflectional endings for verb classes) for the following reason: a paradigm acts as both an abstraction, in that it defines classes, as well as a structured object, with a clustering of different behaviors. When an object is assigned to a particular paradigm, it assumes the set of behaviors characteristic of that entire class. So it is with such artifactual nominals. There are many such subsystems in the lexicon, each with their own internM consistency represented by unique paradigms. This idc~ is explored in detail in/Pustejovsky and Anick 1988/.</Paragraph>
    </Section>
  </Section>
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