Lazy narrowing: Strong completeness and eager variable elimination
نویسندگان
چکیده
منابع مشابه
Lazy Narrowing: Strong Completeness and Eager Variable Elimination (Extended Abstract)
Narrowing is an important method for solving unification problems in equational theories that are presented by confluent term rewriting systems. Because narrowing is a rather complicated operation, several authors studied calculi in which narrowing is replaced by more simple inference rules. This paper is concerned with one such calculus. Contrary to what has been stated in the literature, we s...
متن کاملLazy Narrowing: Strong Completeness and Eager Variable Elimination
Narrowing is an important method for solving uniication problems in equational theories that are presented by connuent term rewriting systems. Because narrowing is a rather complicated operation, several authors studied calculi in which narrowing is replaced by more simple inference rules. This paper is concerned with one such calculus. Contrary to what has been stated in the literature, we sho...
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In this paper we extend the lazy narrowing calculus of Middeldorp, Okui, and Ida 13] to conditional rewrite systems. We show that our calculus is strongly complete whenever basic conditional narrowing is complete. This generalizes one of the three main results of 13] to the conditional case. As a corollary we obtain the strong completeness for three classes of conditional rewrite systems, one o...
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Efficient processing of aggregation queries is essential for decision support applications. This paper describes a class of query transformations, called eager aggregation and laty aggregation, that allows a query optimizer to move group-by operations up and down the query tree. Eager aggregation partially pushes a groupby past a join. After a group-by is partially pushed down, we still need to...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 1996
ISSN: 0304-3975
DOI: 10.1016/0304-3975(96)00071-0