Strong Stubborn Set Pruning for Star-Topology Decoupled State Space Search

Decoupled Strong Stubborn Sets

Recent work has introduced fork-decoupled search, addressing classical planning problems where a single center component provides preconditions for several leaf components. Given a fixed center path ⇡ C , the leaf moves compliant with ⇡C can then be scheduled independently for each leaf. Forkdecoupled search thus searches over center paths only, maintaining the compliant paths for each leaf sep...

Symmetry Breaking in Star-Topology Decoupled Search

Symmetry breaking is a well-known method for search reduction. It identifies state-space symmetries prior to search, and prunes symmetric states during search. A recent proposal, star-topology decoupled search, is to search not in the state space, but in a factored version thereof, which avoids the multiplication of states across leaf components in an underlying star-topology structure. We show...

Decoupled Strong Stubborn Sets (Extended Abstract)

Decoupled State Space Search – Dissertation Abstract

Decoupled State Space Search is a recent approach to exploiting problem structure in classical planning. The particular structure needed is a star topology, with a single center component interacting with multiple leaf components. All interaction of the leaves with the rest of the problem has to be via the center. Given this kind of problem decomposition, we have showed that search on this refo...

Succinct Set-Encoding for State-Space Search

We introduce the level-ordered edge sequence (LOES), a succinct encoding for state-sets based on prefix-trees. For use in state-space search, we give algorithms for member testing and element hashing with runtime dependent only on state size, as well as time and memory efficient construction of and iteration over such sets. Finally we compare LOES to binary decision diagrams (BDDs) and explicit...