Heuristic Search in Cyclic AND/OR Graphs

Heuristic search algorithms can find solutions that take the form of a simple path (A*), a tree or an acyclic graph (AO*). We present a novel generalization of heuristic search (called LAO*) that can find solutions with loops, that is, solutions that take the form of a cyclic graph. We show that it can be used to solve Markov decision problems without evaluating the entire state space, giving it an advantage over dynamic-programming algorithms such as policy iteration and value iteration as an approach to stochastic planning.

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