We propose a new formulation of dependency grammar and develop a corresponding axiomatization of syntactic well-formedness with a natural reading as a concurrent constraint program. We demonstrate the expressivity and effectiveness of set constraints, and describe a treatment of ambiguity with wide applicability. Further, we provide a constraint programming account of dependent disjunctions that is both simple and efficient and additionally provides the benefits of constructive disjunctions. Our approach was implemented in Oz and yields parsers with very good performance for our currently middle scale grammars. Constraint propagation can be observed to be remarkably effective in pruning the search space.

We present an approach to the parsing of dependency structures which. brings together the notion of parsing as candidate elimination, the use of graded constraints, and the parallel disambiguation of related structural representations. The approach aims at an increased level of robustness by accepting constraint violations in a controlled way, combining redundant and possibly conflicting information on different represenrational levels, and facilitating partial parsing as a natural mode of behavior.

This course demonstrates how constraint programming can be used effectively in practice, for linguistic applications. It shows how many forms of ambiguity arising in computational linguistic can be represented compactly and elegantly, and processed efficiently with constraints.

. We describe the design, implementation, and performance of a constraint solver intended to speed up two subtasks of generation in the speech--to--speech translation system Verbmobil. The main requirements for the program were the ability to employ and combine di#erent solving methods, extendability of the framework, and flexibility in interfacing with applications by an intuitive API. Subsequent evaluation of the program with constraint--based representations of the two generation problems showed significant improvement over the previous approaches. 1 Introduction 1.1 Motivation For the natural language translation system Verbmobil, we examined the possibilities for improving the speed of its generation component while clearly separating knowledge sources and algorithms. The component transforms an interlingua semantic representation of speech discourse into phrase structure trees constructed according to a target language grammar (English, Japanese or German) that can subs...