A heuristic function h$h (n)$ is...
- ConsistentConsistent if the estimated cost from node n$n$ to the goal is no greater than the step cost to its successor n'$n'$ plus the estimated cost from the successor to the goal.
- AdmissibleAdmissible if h$h(n)$ never overestimates the true cost to the goal state.
The textbook for my Artificial Intelligence course states that consistency is stronger than admissibility but does not prove it, and I'm having trouble coming up with a mathematical explanation.