Method of operating an expert system and computer systems therefor.

摘要

A rule-based expert system includes a facility for determining a recent previous consistent state of execution after a change is made to a rule or variable. Several queues contain state history information of an inference engine. When changes are made to a rule or variable, these history queues are examined to determine a recent consistent state. If the current state is inconsistent due to the change, the user can be informed that the system is now in an inconsistent state. <IMAGE>