AI branching factor

If the branching factor is large, the breadth-first search "OPEN list" may run out of memory. But if the number of states is so large, the statespace graph probably cannot开发者_运维知识库 be drawn or represented in memory. So is it not the case that all forms of search will fail?

Not necessarily - it could be that the state being searched for will be located at a fairly shallow position in the tree (thus being found before memory is exhausted), or (if the tree isn't too deep), you could use depth-first search instead. Also, pruning techniques might help you reduce the effective branching factor by revealing that some paths don't need to be followed.