ParseTalk about Textual Ellipsis

orated model of functional preferences on C f elements which constrains the set of possible antecedents according to topic/comment patterns. 8 Conclusion In this paper, we have outlined a model of text ellipsis parsing. It considers conceptual criteria to be of primary importance and provides a proximity measure in order to assess various possible antecedents for consideration of proper bridges (Clark, 1975) to elliptical expressions. In addition, functional constraints based on topic/comment patterns contribute further restrictions on proper elliptical antecedents. The particular advantage of our approach lies in the integrated treatment of text-level ellipsis within a single coherent grammar format. The anaphora resolution module (Strube and Hahn, 1995) and the ellipsis handler have both been implemented in Smalltalk as part of a comprehensive text parser for German. Besides the information technology domain, experiments with our parser have also been successfully run on medical domain texts, thus indicating that the heuristics we have been developing are not bound to a particular domain. The current lexicon contains a hierarchy of approximately 70 word class speciications with nearly 2.500 lexical entries and corresponding concept descriptions available from the LOOM knowledge representation system (MacGregor and Bates, 1987) | 650 and 400 concept/role specii-cations for the information technology and medicine domain, resp. Acknowledgments. We would like to thank our colleagues in the CLIF group who read earlier versions of this paper. In particular, improvements are due to discussions we had with N. Actors: A conceptual foundation for concurrent object-oriented programming. Making understanders out of parsers: Semantically driven parsing as a key concept for realistic text understanding applications. and Lte-Lite-25, which form the current forward-looking centers. The terminologi-cal reasoner attempts to determine a role chain between one of these instances and Cpu. Only Pci-Motherboard passes this test successfully. Both concepts can be linked via the has-cpu role at unit length (depth) 1. Consider a slight variation of text fragment (1): If PCI-Motherboard in (1) is replaced by LCD-Display (as in (2)) the result of the ellipsis resolution diiers from the previous example. Since due to conceptual constraints Lcd-display cannot be considered a proper antecedent of Cpu, Lte-Lite-25 is selected as the only valid antecedent.