tailieunhanh - Báo cáo khoa học: "DISCOURSE RELATIONS AND DEFEASIBLE KNOWLEDGE*"

This paper presents a formal account of the temporal interpretation of text. The distinct natural interpretations of texts with similar syntax are explained in terms of defeasible rules characterising causal laws and Gricean-style pragmatic maxims. Intuitively compelling patterns of defea,sible entailment that are supported by the logic in which the theory is expressed are shown to underly temporal interpretation. | Discourse Relations and Alex Lascarides Human Communication Research Centre University of Edinburgh 2 Buccleuch Place Edinburgh EH8 9LW Scotland Defeasible Knowledge Nicholas Asher Center for Cognitive Science University of Texas Austin Texas 78712 USA Abstract This paper presents a formal account of the temporal interpretation of text. The distinct natural interpretations of texts with similar syntax are explained in terms of defeasible rules characterising causal laws and Gricean-style pragmatic maxims. Intuitively compelling patterns of defeasible entailment that are supported by the logic in which the theory is expressed are shown to un-derly temporal interpretation. The Problem The temporal interpretation of text involves an account of how the events described are related to each other. These relations follow from the discourse relations that are central to temporal import. 1 Some of these are listed below where the clause a appears in the text before Narration a P The event described in is a consequence of but not necessarily caused by the event described in a 1 Max stood up. John greeted him. E labor ation a P The event described in p contributes to the occurrence of the culmination This paper is greatly influenced by work reported in Lascarides Í Oberlander 1991 . We would like to thank Hans Kamp Michael Morreau and Jon Oberlander for their significant contributions to the content of this paper. All mistakes are solely our responsibility. iThe support of the Science and Engineering Research Council through project number GR G22077 is gratefully acknowledged. HCRC is supported by the Economic and Social Research Council. 1 Extensive classifications of discourse relations are offered in Polanyi 1985 Scha Polanyi 1988 and Thompson Mann 1987 . of the event described in a . P s event is part of the preparatory phase of a s 2 2 The council built the bridge. The architect drew up the plans. Explanationịa P For .