However, the distinction between the propose step and the verify step is relative. We can make the propose step gradually more knowledge intensive by including more knowledge of the knowledge-verification step in the propose step. We can make the propose step less knowledge intensive by generating arbitrary methods, without using the static goals for guiding the proposal of a method. In our case the knowledge about diagnostic methods enables us to guide the propose step using the static goals. If verification failed a new propose step will be performed.
Diagnosis is performed using the valid method of the knowledge-verification step.
The computed diagnoses are used for testing the dynamic goals. The verification of the dynamic goals requires the computed diagnoses. Computing these diagnoses is expensive, and therefore the simulation-verification is expensive. An examples of a dynamic goals is a requirement on the size of the diagnoses. In such a case we have to verify this goal dynamically.