tailieunhanh - Báo cáo khoa học: "Constraints over Lambda-Structures in Semantic Under specification"

We introduce a first-order language for semantic underspecification that we call Constraint Language for Lambda-Structures (CLLS). A Astructure can be considered as a A-term up to consistent renaming of bound variables (aequality); a constraint of CLLS is an underspecified description of a A-structure. CLLS solves a capturing problem omnipresent in underspecified scope representations. CLLS features constraints for dominance, lambda binding, parallelism, and anaphoric links. Based on CLLS we present a simple, integrated, and underspecified treatment of scope, parallelism, and anaphora. . | Constraints over Lambda-Structures in Semantic Underspecification Markus Egg and Joachim Niehren and Peter Ruhrberg and Feiyu Xu Department of Computational Linguistics Programming Systems Lab Universitat des Saarlandes Saarbriicken Germany egg peru Abstract We introduce a first-order language for semantic underspecification that we call Constraint Language for Lambda-Structures CLLS . A A-structure can be considered as a A-term up to consistent renaming of bound variables a-equality a constraint of CLLS is an underspecified description of a A-structure. CLLS solves a capturing problem omnipresent in underspecified scope representations. CLLS features constraints for dominance lambda binding parallelism and anaphoric links. Based on CLLS we present a simple integrated and underspecified treatment of scope parallelism and anaphora. 1 Introduction A central concern of semantic underspecification van Deemter and Peters 1996 is the underspecification of the scope of variable binding operators such as quantifiers Hobbs and Shieber 1987 Alshawi 1990 Reyle 1993 . This immediately raises the conceptual problem of how to avoid variable-capturing when instantiating underspecified scope representations. In principle capturing may occur in all formalisms for structural underspecification which represent binding relations by the coordination of variables Reyle 1995 Pinkal 1996 Bos 1996 Niehren et al. 1997a . Consider for instance the verb phrase in 1 Manfred vp knows every student An underspecified description of the compositional semantics of the VP in 1 might be given along the lines of 2 2 X C1 Vz student z C2 know z z The meta-variable X in 2 denotes some tree representing a predicate logic formula which is underspecified for quantifier scope by means of two place holders Cl and C2 where a subjectquantifier can be filled in and a place holder z for the subject-variable. The binding of the object-variable z by the object-quantifier