Principle Based Semantics for HPSG

Principle Based Semantics for HPSG Anette Frank and Uwe Reyle Institute for Computational Linguistics University of Stuttgart Azenbergstr.12, D-70174 Stuttgart, Germany e-mail: uwe@ims.uni-stuttgart.de Abstract The paper presents a constraint based semantic formalism for HPSG. The syntax-semantics inter- face directly implements syntactic conditions on quantifier scoping and distributivity. 1 The con- struction of semantic representations is guided" by general principles governing the interaction bet- ween syntax and semantics. Each of these princip- les acts as a constraint to narrow down the set of possible interpretations of a sentence. Meanings of ambiguous sentences are represented by single partial representations (so-called U(nderspecified) D(iscourse) R(epresentation) S(tructure)s) to which further constraints can be added monotonically to gain more information about the content of a sent- ence. There is no need to build up a large number of alternative representations of the sentence which are then filtered by subsequent discourse and world knowledge. The advantage of UDRSs is not only that they allow for monotonic incremental interpretation but also that they are equipped with truth condi- tions and a proof theory that allows for inferences to be drawn directly on structures where quantifier scope is not resolved. 1 Introduction The semantic analysis of standard HPSG deviates from the familiar Montegovian way to construct se- mantic representations mainly in that it uses unifica- tion to eliminate the need for 13-reduction. Variables 1In the present paper we do only focus on simple principles restricting scope ambiguities and ambiguities resulting from plural NPs in English. For German re- strictions on scope are much more complicated because they cannot be stated independently of scrambling phe- nomena. In (l~-ank/Reyle 1994) the present approach is worked out for a fragment of German that deals with (i) quantifier scope ambiguities triggered by scrambling and/or movement and (ii) ambiguities that arise from the collective/distributive distinction of plural NPs. The underlying scope theory for German was developed in (Frey 1993). The analysis in (Frank/Reyle 1994) departs significantly from our earlier account in (Frank/Reyle 1992), where monotonicity was not ensured. 9 are bound to argument positions by the close inter- play between syntactic and semantic processing; and the semantics of constituents is determined by the Semantics Principle, which governs the way of unify- ing the semantics of daughter constituents to build up the semantic value of the phrasal constituent: The CONTENT value is projected from the seman- tic head, which is defined as the syntactic HEAD- DTR in head-comp-structures, but as the ADJ-DTR in head-adjunct structures. It is important to note that the semantic contribution of quantified verb ar- guments is not completely projected as part of the CONTENT value. The meaning of such NPs splits into the features QUANTS, a list representing the information about quantifier scope, and NUCLEUS, containing the nonquantificational core. In the ge- neral case only the NUCLEUS is projected from the semantic head according to the Semantics Principle, while the QUANTS value gets instantiated stepwisc in interaction with the quantifier storage mechanism (Cooper Store). The mechanism of Cooper storage is built …

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