Sacerdoti introduced the notion of criticality number to aid in
The basic assumption is that satisfying a lower-criticality goal will
never undo a higher-criticality goal.
- Each type of goal is given a criticality number that indicates
how difficult it is to achieve.
- Planning is done for the highest-criticality goals first.
- In planning for a given criticality level, preconditions at
lower criticality levels are ignored.
- A plan is successively refined by filling in the lower-numbered
goals and preconditions.