Paper: Default Reasoning In Natural Language Processing

ACL ID C88-2163
Title Default Reasoning In Natural Language Processing
Venue International Conference on Computational Linguistics
Session Main Conference
Year 1988

In natural )a~gnage, as in other computational task domains it is impox~ant tc~ operate by default assumptions. First, m~my con- straints re(tni~'exl h)r constraint propagation are initially tmspecified, Second, in highly ambiguous tasks such as text analysis, ambiguity can be reduced by considering more plansi-. hie scenarios first. Default reasoning is problematic for first- order logic when allowing non-monotonic inferences. Whereas in monotonic logic facts can only be asserted, in non-monotonic logk: a system must be maintained consistent even as previously assumed defaults are being retracted. Non~monotoniety is pervasive in natural language due to the seri- al nature of utterances. When reading text left-to-fight, it hap- pens that default assumptions made early in the sentence must ...