Approximate Evaluation of Logic Programs

扩展表是逻辑程序的备忘结构，它将谓词的扩展保存在表中。随后的调用（其答案在表中）使用表查找而不是重新计算结果。由于保存的术语不一定是基本事实，因此使用对Prolog术语的诱导包容排序来避免在表中保存冗余信息。这种重复消除机制将被扩展，允许指定次序，而不是由包含Prolog术语给出的次序。这种增强的功能修改了执行方法的行为，以提供基于这些顺序的逻辑程序的近似评估。

Extension tables are a memo structure for logic programs that save the extension of a predicate in a table. Subsequent calls, whose answers are in the table, use a table lookup rather than recomputing the results. Since the terms that are saved are not necessarily ground facts, the induced subsumption ordering on Prolog terms is used to avoid saving redundant information in the table. This duplicate elimination mechanism will be extended by allowing for the specification of orderings other than those given by the subsumption of Prolog terms. This enhanced capability modifies the behavior of the execution method to provide an approximate evaluation of the logic program based on these orderings.