Roy Feldman, Paul Morris
We introduce methods for identifying operator preconditions that need not be expanded further. The methods are proved to be admissible, that is, they will not cause a solution to be missed when one exists. In certain cases, the methods also identify operator reformulations that increase the number of nonexpandable preconditions. This approach provides effective loop control in common situations. Moreover, the computation required can be performed during a precompilation of the operators in a domain; thus, there is no significant additional run-time overhead during planning.