Exploiting Symmetries by Planning for a Descriptive Quotient

We eliminate symmetry from a problem before searching for a plan. The planning problem with symmetries is decomposed into a set of isomorphic subproblems. One plan is computed for a small planning problem posed by a descriptive quotient, a description of any such subproblem. A concrete plan is synthesized by concatenating instantiations of that one plan for each subproblem. Our approach is sound.