AI - Heuristic function requirements

Question

I have a question about Huristic function in Artificial Intelligence (AI). I know that we should look for monotonic and admissible heuristic function.

I have two questions:

1. Why is it required that the function will be admissible?

2. What are the advantages of monotonic heuristic functions?

Thank you!

Answer 1

An admissible heuristic is one that provides a lower bound estimate to the goal state.

A monotonic (also known as consistent) heuristic will allow you to implement an optimal A* search efficiently. It guarantees optimality if you visit each state only once.