Paulo Jorge de Sousa Azevedo

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This paper discusses the relationship between tabulation and goal-oriented bottom-up evaluation of logic programs. Some diierences emerge when one tries to identify features of one evaluation method in the other. We show that to obtain the same eeect as tabulation in top-down, one has to perform a careful adornment in programs to be evaluated bottom-up.(More)
Deductive databases with updates in rule bodies do not allow to use bottom-up execution model. This is due to the introduction of control in rule bodies induced by update sequences. However, bottom-up strategies are very important due to the set oriented query-answering process of database systems. In 7] an extended rule language was proposed that allows to(More)
In this thesis we investigate techniques for preventing recomputation in the execution of logic programs. One can reduce recomputation by eliminating subquery redundancy. This can be achieved by storing intermediate results, which are shared between identical subqueries. This is known as the tabulation technique. We consider top-down evaluation procedures(More)
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