Components of a node
State: the state in the state space to which the node
corresponds
Parent-node: the node in the search tree that
generated this node
Action: the action that was applied to the parent to
generate the node
Path-cost: the cost, traditionally denoted by g(n),
of the path from the initial state to the node, as
indicated by the parent pointers
Depth: the number of steps along the path from the
initial state