摘要
Several extensions of the logic programming language Prolog to non Horn clauses use case analysis to handle non-Horn clauses. In this paper, analytical and empirical evidences are presented to show that, by making a set of clauses less 'non-Horn' using predicate renaming, the performance of these case-analysis based procedures can be improved significantly. In addition, the paper also investigated the problem of efficiently constructing a predicate renaming that reduces the degree of 'non-Hornness' of a clause set maximally. It is shown that this problem of finding a predicate renaming to achieve minimal 'non-Hornness' is NP-complete.
Several extensions of the logic programming language Prolog to non Horn clauses use case analysis to handle non-Horn clauses. In this paper, analytical and empirical evidences are presented to show that, by making a set of clauses less 'non-Horn' using predicate renaming, the performance of these case-analysis based procedures can be improved significantly. In addition, the paper also investigated the problem of efficiently constructing a predicate renaming that reduces the degree of 'non-Hornness' of a clause set maximally. It is shown that this problem of finding a predicate renaming to achieve minimal 'non-Hornness' is NP-complete.
