tailieunhanh - Báo cáo khoa học: "A Tradeoff between Compositionality and Complexity in the Semantics of Dimensional Adjectives"

Linguistic access to uncertain quantitative knowledge about physical properties is provided by d i m e n s i o n a l adjectives, . long-short in the spatial and temporal senses, near-far, fast-slow, etc. Semantic analyses of the dimensional adjectives differ on whether the meaning of the differential comparative (6 cm shorter than) and the equative with factor term (three times as long as) is a compositional function of the meanings the difference and factor terms (6 cm and three times) and the meanings of the simple comparative and equative, respectively. The compositional treatment comes at the price. | A Tradeoff between Compositionality and Complexity in the Semantics of Dimensional Adjectives Geoffrey Simmons Graduiertenkolleg Kognitionswissenschaft Universitât Hamburg Bodenstedtstr. 16 D-W-2000 Hamburg 50 Germany e-mail simmons@ Abstract Linguistic access to uncertain quantitative knowledge about physical properties is provided by dimensional adjectives . long-short in the spatial and temporal senses near-far fast-slow etc. Semantic analyses of the dimensional adjectives differ on whether the meaning of the differential comparative 6 cm shorter than and the equative with factor term three times as long as is a compositional function of the meanings the difference and factor terms 6 cm and three times and the meanings of the simple comparative and equative respectively. The compositional treatment comes at the price of a meaning representation that some authors Pinkal 1990 Klein 1991 find objectionally un-parsimonious. In this paper I compare semantic approaches by investigating the complexity of reasoning that they entail specifically I show the complexity of constraint propagation over real-valued intervals using the Waltz algorithm in a system where the meaning representations of sentences appear as constraints cf. Davis 1987 . It turns out that the compositional account is more complex on this measure. However I argue that we face a tradeoff rather than a knock-down argument against compositionality since the increased complexity of the compositional approach may be manageable if certain assumptions about the application domain can be made. TOPIC AREAS semantics Al-methods in computational linguistics 1 Introduction In the past decade the field of knowledge representation KR has seen impressive growth of sophistication in the representation of uncertain quantitative knowledge about physical properties in commonsense reasoning and qualitative physics. The input to most of these systems is entered by hand but some of them .