A* attempts to solve the broad movement issue of UCS and tries to make its movement more directed/biased towards the goal state.

Adding a Heuristic Value

It does this by adding a heuristic value to the total cost of a state path.

The Heuristic Value of a state n: $h^{*} (n)$ should follow the following rules:

$h^{*} (n) \leq h (n)$
- it must be at MOST as large as the actual cost to the goal state
Monotonicity This heuristic value should generally be

Admissible heuristics can be derived from exact solution of relaxed problems. (Google this)

Example

… 1

Thumbnail	Note	Type