Hypothetical datalog: complexity and expressibility
نویسندگان
چکیده
منابع مشابه
Hypothetical Datalog : Complexity
We present an extension of Horn-clause logic which can hypothetically add and delete tuples from a database. Such logics have been discussed in the literature , but their complexities and expressibilities have remained an open question. This paper examines two such logics in the function-free, predicate case. It is shown, in particular, that augmenting Horn-clause logic with hypothetical additi...
متن کاملHypothetical Datalog: Complexity and Expressiblity
We present an extension of Horn-clause logic which can hypothetically add and delete tuples from a database. Such logics have been discussed in the literature, but their complexities and expressibilities have remained an open question. This paper examines two such logics in the function-free, predicate case. It is shown, in particular, that augmenting Horn-clause logic with hypothetical additio...
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It is shown that the time needed by a concurrent read concurrent write parallel random access machine CRAM to check if an input has a certain property is the same as the minimal depth of a rst order inductive de nition of the property This in turn is equal to the number of iterations of a rst order sentence needed to express the property The second contribution of this paper is the introduction...
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Hypothetical Datalog is based on an intuitionistic semantics rather than on a classical logic semantics, and embedded implications are allowed in rule bodies. While the usual implication (i.e., the neck of a Horn clause) stands for inferring facts, an embedded implication plays the role of assuming its premise for deriving its consequence. A former work introduced both a formal framework and a ...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 1990
ISSN: 0304-3975
DOI: 10.1016/0304-3975(90)90011-6