Oberlander, J. and A. Lascarides, [1992] Preventing False Temporal Implicatures: Interactive Defaults for Text Generation, in Proceedings of COLING92, pp721--727, Nantes France, July 1992.
Given the causal and temporal relations between events in a knowledge base, what are the ways they can be described in text?
Elsewhere, we have argued that during interpretation, the reader-hearer H must infer certain temporal information from knowledge about the world, language use and pragmatics. It is generally agreed that processes of Gricean implicature help determine the interpretation of text in context. But without a notion of logical consequence to underwrite them, the inferences---often defeasible in nature---will appear arbitrary, and unprincipled. Hence, we have explored the requirements on a formal model of temporal implicature, and outlined one possible nonmonotonic framework for discourse interpretation (Lascarides and Asher [1991], Lascarides and Oberlander [1992a]).
Here, we argue that if the writer-speaker S is to tailor text to H, then discourse generation can be informed by a similar formal model of implicature. We suggest two ways to do it: a version of Hobbs et al's [1988, 1990] Generation as Abduction; and the Interactive Defaults strategy introduced by Joshi et al [1984a, 1984b, 1986]. In investigating the latter strategy, the basic goal is to determine how notions of temporal reliability, precision and coherence can be used by a nonmonotonic logic to constrain the space of possible utterances. We explore a defeasible reasoning framework in which the interactions between the relative knowledge bases of S and H helps do this. Finally, we briefly discuss limitations of the strategy: in particular, its apparent marginalisation of discourse structure.
The paper focuses very specifically on implicatures of a temporal nature. To examine the relevant examples in sufficient detail, we have had to exclude discussion of many closely related issues in the theory of discourse structure. To motivate this restriction, let us therefore consider first why we might want to generate discourses with structures which lead to temporal complexities.
@inproceedings{oberlander:lascarides:1992,
author = {Jon Oberlander and Alex Lascarides},
year = {1992},
title = {Preventing False Temporal
Implicatures: Interactive Defaults for Text Generation},
booktitle = {Proceedings of the International Conference in Computational Linguistics (COLING)},
pages = {721--727},
address = {Nantes, France}
}