The Complexity of the Evaluation of Complex Algebra Expressions
نویسندگان
چکیده
The Abiteboul and Beeri algebra for complex objects can express a query whose meaning is transitive closure, but the algorithm naturally associated to this query needs exponential space. We show that any other query in the algebra which expresses transitive closure needs exponential space, under a \call by value" evaluation strategy. This proves that in general the powerset is an intractable operator for implementing xpoint queries.
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ورودعنوان ژورنال:
- J. Comput. Syst. Sci.
دوره 55 شماره
صفحات -
تاریخ انتشار 1997