A* Search: Concluded
An h’ that never overestimates h is called an admissible search heuristic.
A* search defined to be best-first with an admissible h
Graceful degradation: suppose h’ is not admissible, but doesn’t miss by much?
- If the probability that h'(s)>h(s) is less than ?, then the probability that A* will return an answer that is sub-optimal by more than a factor of ? is small.