6. In an expert system for inputting and uninterrupted processing of facts, a method of producing explanations comprising the steps of: (a) inputting facts for processing in an inference engine; (b) searching a rule base grouped into rule classes, each rule class containing one or more rules, the rule classes being related to one another in a dependence table and wherein the rule classes are arranged in a tree structure of nodes; (c) firing a rule selected by the inference engine from the facts; (d) determining whether the fired rule is a first fired rule in a rule class; (e) if the fired rule is a first fired rule in a rule class, creating a frame for the rule class of the first fired rule; (f) adding to the created frame one or more explanations related to the rule class of the first fired rule; (g) analyzing the facts with the inference engine for any further rule which can be fired and repeating steps (b) through (f) until no more rules remain in the rule base to be fired; and (h) outputting conclusions and explanations generated by the expert system from the inputted facts.
6. In an expert system for inputting and uninterrupted processing of facts, a method of producing explanations comprising the steps of: (a) inputting facts for processing in an inference engine; (b) searching a rule base grouped into rule classes, each rule class containing one or more rules, the rule classes being related to one another in a dependence table and wherein the rule classes are arranged in a tree structure of nodes; (c) firing a rule selected by the inference engine from the facts; (d) determining whether the fired rule is a first fired rule in a rule class; (e) if the fired rule is a first fired rule in a rule class, creating a frame for the rule class of the first fired rule; (f) adding to the created frame one or more explanations related to the rule class of the first fired rule; (g) analyzing the facts with the inference engine for any further rule which can be fired and repeating steps (b) through (f) until no more rules remain in the rule base to be fired; and (h) outputting conclusions and explanations generated by the expert system from the inputted facts. 7. The method of claim 6 further comprising the step of placing each created frame at a node in the tree structure related to the fired rule.