System and method for producing discrimination nets for expert systems

摘要

An expression comprising conditions is evaluated based on values of data elements presented to a network of a kind in which the conditions are represented by nodes and the relationships among conditions in the expression are represented by links among the nodes, by storing information that identifies which conditions represented by at least some of the nodes have been satisfied by the values of the data elements, and testing the stored information in accordance with the expression as a basis for evaluating said expression. In a second aspect, an expression that comprises conditions which pertain to possible values of data belonging to categories of data is evaluated based on actual values of data presented to a network of a kind in which the conditions are represented by nodes, by identifying a category of data for which values need not occur in the network in order for a condition that requires a value in the category to be provisionally satisfied, and causing the node that represents the condition to indicate that the condition is provisionally satisfied even when no values in the identified category occur in the network.