A Consideration on the Expression of Instantiations in a Production System

Abstract

This paper proposes a method for dealing with a certain kind of expensive production, contriving the expression of instantiations (ordered subsets of working memory elements). Expensive productions are rules which would be required the extraordinary time and space to match (for each rule, compare the left-hand side against the current working memory). The object expensive productions are such that the left-hand side can be decomposed into plural sets of interdependent condition elements. We introduce a new simple notation expressing plural instantiations satisfying a rule's left-hand side, using direct products combining subsets of working memory elements. By this notation, computer loads of executing expensive productions can be reduced. Moreover, empirical and analytic results demonstrate that the new instantiation's expression can substantially reduce the execution time of production system programs.