Complete and Efficient Methods Cuts in And-Or

Practical Prolog programs usually contain extralogical features like cuts, side-effects, an.d database manipulating predicates. In order to exploit implicit parallelism from real applications a parallcl logic programming system should necessarily support these features. In this paper we show how Prolog’s extra-logical features can be supported an an and-or parallel logic programming system. We show that to support extralogical features an and-or parallel logic programming system should recompute the solutions to independent goals instead of sharing them. We describe an abstraction called the Composition Tree for representing andor parallel ezecution with recomputation. We introduce the notion of ‘Vocal-leftmostness” in the Composition Tree and use it for deriving com.plete and efficient methods for supporting extra-logical predicates in and-or parallel logic programmirzg systems based on the Composition Tree abstraction.