## Defaults and Revision in Structured Theories (1991)

Venue: | In Proceedings of the IEEE Symposium on Logic in Computer Science (LICS'91 |

Citations: | 33 - 15 self |

### BibTeX

@INPROCEEDINGS{Ryan91defaultsand,

author = {Mark Ryan},

title = {Defaults and Revision in Structured Theories},

booktitle = {In Proceedings of the IEEE Symposium on Logic in Computer Science (LICS'91},

year = {1991},

pages = {362--373},

publisher = {Society Press}

}

### Years of Citing Articles

### OpenURL

### Abstract

Starting from a logic which specifies how to make deductions from a set of sentences (a `flat theory'), a way to generalise this to a partially ordered bag of sentences (a `structured theory') is given. The partial order is used to resolve conflicts. If OE occurs below / then / is accepted only insofar as it does not conflict with OE. We start with a language L, a set of interpretations M and a satisfaction relation fl ` M \Theta L. The key idea is to define, for each structured theory, a pre-order on interpretations. Models of the structured theory are defined to be maximal interpretations in the ordering. They are shown to exist if the logic hL; M; fli is compact. A revision operator is defined, which takes a structured theory and a sentence and returns a structured theory. The consequence relation has the properties of weak monotonicity, weak cut and weak reflexivity with respect to this operator, but fails their strong counterparts. 1 Introduction Ordering sentences in a theo...

### Citations

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Specification Revision and Defaults
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