Semantics of Portions and Partitive Nouns for NLP

Semantics of Portions and Partitive Nouns for NLP Salvador Climent Facultat de Filologia, Sccci6 Lingtifstica General Universitat de Barcelona Gran Via 585 08007 Barcelona Spain climent@ goliat.upc.cs Abstract This paper describes a system of representation of nouns denoting portions, segments and relative quantities of entities, in order to account for this case of part-whole relationship. The semantics of both constructions denoting portions aad nouns used to build them arc discussed and eventually formalised in a unification-based formalism (LKB-IA~L) in terms of Pustciovsky's Theory of Qualia and Jackendoff's Conceptual Semantics. 1. Introduction and Motivation Processes of inference of meaning concerning part- whole relations can be drawn from a lexicon bearing meronymic links between words (ef. [WAI~881) e.g. component-whole links (hand-arm), member- collection (tree-forest) and so. The case of portions, segments and relalivc quantities of objects or substances (slices, lumps, buckets, spoon.rids, grains, tops or tips of things) is the exception, since this is a relation which is encoded in the language by means of constructions. Coutrm'y to that which some authors posit ([CIIAS8], [WIN87]), it doesn't seem to be a productive linguistic gencr~disation to set in a lexicon some part-of link between slice and cake. In any case, such relalion would exist between cake and slice of cake -namely, the part-of relalion shouhl stand between slice and any sliceable thing. Generally speaking, the relation portion may be charactcriscd, semantically, in Ihat lhe whole pre- exists the part and the part retains most of the properties of lhe whole ([IRI88]), and, syntactically, as surfacing in <X of NP> structures, being potentially <X> an apparently heterogeneous collection of words which, henceforlh, billowing [CO1×)2] We will refer to ~ts Partitive Nouns (l'Ns). On Ihc other hand, portions denoted by such constructions differ from their wholes in some aspects, basically iudividuation, quantity, process of bringing about, and shalx:. Such properties, since they are present in <X of NI~ but they were not in <N1)>, are assumed to be carried to the coustruclion by the noun (<X>). I'll try to show here Ihat it is plausible to give a glob~d account of such heterogeneous set of words, since they bear a range of common and distinctive linguistic features, and 1'11 try to provide a representation feasible for NLP which account both for PNs as a general class and for the homogeneous subclasses which wilhin them could be distinguished and defined 1. 2. Framework We assume some general familiarity with the framework Wc work within: LKB-I,Pd~ ([CO1×32]) as a formalism of computational representation, The Geueralive Lexicon ([P[ 1S95 I) as a theoretical ground lbr the fonmdisatiou of lexical signs, and Conceptual Semantics ([JAC91]) for the conceptualisation of parts and Ixmndaries of entities. LKB-I~RL is an IIPSG-liko formalism based on typed feature structures ([CAR92]) developed within the Acquilex Project which makes use of unification and mechanisms of defaull inheritance. There are four basic levels of representation: ()RTII, CAT, SEM and RQS. CAT encodes syntax using a eategorial grammar approach, so there are simple (e.g. noun: N) and complex …

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