Given that there is more than one possible operator which should we choose? Only one is necessary - so we go for the `easiest'. Here - we choose the goal with the least number of subgoals that need to be generated (again, not necessarily the best choice).
Consider the problem below. Can you work through the example to develop the plan shown? The problem is easier than the one we have looked at so far since there is only one operator schema. =12cm /home/dream4/paul/teaching/ai1problemsolving/slides/strips/slideworkedex1a.eps