tailieunhanh - Báo cáo khoa học: "A Uniform Approach to Underspecification and Parallelism"

We propose a unified framework in which to treat semantic underspecification and parallelism phenomena in discourse. The framework employs a constraint language that can express equality and subtree relations between finite trees. In addition, our constraint language can express the equality up-to relation over trees which captures parallelism between them. The constraints are solved by context unification. We demonstrate the use of our framework at the examples of quantifier scope, ellipsis, and their interaction. . | A Uniform Approach to Underspecification and Parallelism Joachim Niehren Programming Systems Lab Universităt des Saarlandes Saarbriicken Germany Manfred Pinkal Department of Computational Linguistics Universitat des Saarlandes Saarbriicken Germany pinkal@ Peter Ruhrberg Department of Computational Linguistics Universităt des Saarlandes Saarbrucken Germany peru@ Abstract We propose a unified framework in which to treat semantic underspecification and parallelism phenomena in discourse. The framework employs a constraint language that can express equality and subtree relations between finite trees. In addition our constraint language can express the equality up-to relation over trees which captures parallelism between them. The constraints are solved by context unification. We demonstrate the use of our framework at the examples of quantifier scope ellipsis and their 1 Introduction Traditional model-theoretic semantics of natural languages Montague 1974 has assumed that semantic information processed by composition and reasoning processes is available in a completely specified form. During the last few years the phenomenon of semantic underspecification . the incomplete availability of semantic information in processing has received increasing attention. Several aspects of underspecification have been focussed upon motivated mainly by computational considerations the ambiguity and openness of lexical meaning Pustejovsky 1995 Copestake and Briscoe 1995 referential underspecification Asher 1993 structural semantic underspecification caused by syntactic ambiguities Egg and Lebeth 1995 and by the underdetermination of scope relations Alshawi and Crouch 1992 Reyle 1993 . In addition external factors such as insufficient coverage The research reported in this paper has been supported by the SFB 378 at the Universitãt des Saarlandes and the Esprit Working Group CCL II EP 22457 . of the grammar .