ISSN:
1573-0670
Keywords:
Deductive database
;
disjunctive database
;
indefinite
;
database
;
inference
;
negation
;
closed world assumption
Source:
Springer Online Journal Archives 1860-2000
Topics:
Computer Science
Notes:
Abstract We propose criteria that any rule for inferring negative information from disjunctive databases should satisfy, and examine existing rules from this viewpoint. We then present a new inference rule, the ‘disjunctive database rule’ (DDR), and compare it to the existing rules with respect to the criteria. In particular, the DDR is equivalent to the CWA for definite databases, it infers no more negative information than the GCWA, and it interprets disjunction inclusively rather than exclusively. We generalize the DDR to a class of layered databases, describe an implementation of the DDR, ‘negation as positive failure’, and study its soundness and completeness properties.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00297247
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