Functional dependencies in Horn theories
نویسندگان
چکیده
منابع مشابه
Functional Dependencies in Horn Theories
This paper studies functional dependencies in Horn theories, both when the theory is represented by its clausal form and when it is deened as the Horn envelope of a set of models. We provide polynomial algorithms for the recognition of whether a given functional dependency holds in a given Horn theory, as well as polynomial algorithms for the generation of some representative sets of functional...
متن کاملFunctional Dependencies in Horn
This paper studies functional dependencies in Horn theories, both when the theory is represented by its clausal form and when it is de ned as the Horn envelope of a set of models. We provide polynomial algorithms for the recognition of whether a given functional dependency holds in a given Horn theory, as well as polynomial algorithms for the generation of some representative sets of functional...
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We extend Fagin’s result on the equivalence between functional dependencies in relational databases and propositional Horn clauses. It is shown that this equivalence still holds for functional dependencies in databases that support complex values via nesting of records, lists, sets and multisets. The equivalence has several implications. Firstly, it extends a well-known result from relational d...
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This paper investigates belief revision where the underlying logic is that governing Horn clauses. We show that classical (AGM) belief revision doesn’t immediately generalise to the Horn case. In particular, a standard construction based on a total preorder over possible worlds may violate the accepted (AGM) postulates. Conversely, in the obvious extension to the AGM approach, Horn revision fun...
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Abduction is a fundamental mode of reasoning, which has taken on increasing importance in Artificial Intelligence (AI) and related disciplines. Computing abductive explanations is an important problem, and there is a growing literature on this subject. We contribute to this endeavor by presenting new results on computing multiple resp. all of the possibly exponentially many explanations of an a...
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ژورنال
عنوان ژورنال: Artificial Intelligence
سال: 1999
ISSN: 0004-3702
DOI: 10.1016/s0004-3702(98)00114-3