A Computational Model for Functional Logic Deductive Databases

Abstract

Abstract. This paper adds the handling of negative information to a functional-logic deductive database language. By adopting as semantics for negation the so-called CRWLF, wherein the negation is intended as 'finite failure' of reduction, we will define Herbrand algebras and models for this semantics and a fix point operator to be used in a new goaldirected bottom-up evaluation mechanism based on magic transformations. This bottom-up evaluation will simulate the top-down one of the original program; in fact, it will carry out a goal-directed lazy evaluation.