Paraconsistent disjunctive deductive databases
نویسندگان
چکیده
منابع مشابه
Disjunctive Deductive Databases
Background material is presented on deductive and normal de-ductive databases. A historical review is presented of work in disjunctive deductive databases, starting from 1982. The semantics of alternative classes of disjunctive databases is reviewed with their model and xpoint characterizations. Algorithms are developed to compute answers to queries in the alternative theories using the concept...
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Practical applications of deductive databases often require the use of extended features like disjunctive information, aggregation operators or default negation. But it has been unclear how one could deal with aggregation in the presense of recursion and disjunction. Usually , there is the requirement that deductive databases must be stratiied w.r.t. aggregation, i.e. a predicate q that is deen...
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The concepts of the dual and complementary databases as alternative representations for a given disjunctive deductive database, DB, are introduced. The dual database results from interchanging the occurrences of OR and AND operators in the positive clause representation of DB. The complementary database is deened to have as minimal models the complements of the minimal models of DB relative to ...
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The basic assumption in relational and deductive databases is that there are no gaps in our knowledge. That is, the database cannot store data that contain null values or data that is indeenite. In practical situations knowledge is not precise, and there are gaps in our knowledge. These gaps may be due to null values in the data, may arise when we combine several databases that lead to inconsis...
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In general, computing answers to queries in disjunctive deductive databases is CoNP-complete and therefore computationally infeasible. However, there are some tractable classes of disjunctive databases. In this paper, we present polynomial time algorithms to compute answers to queries in one such tractable class of disjunctive databases where at most two atoms are allowed in any disjunction.
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 1992
ISSN: 0304-3975
DOI: 10.1016/0304-3975(92)90214-z