The Complexity of Solving Reachability Games Using Value and Strategy Iteration
Abstract
Two standard algorithms for approximately solving two-player zero-sum concurrent reachability games are value iteration and strategy iteration. We prove upper and lower bounds of \(2^{m^{\varTheta(N)}}\) on the worst case number of iterations needed by both of these algorithms for providing non-trivial approximations to the value of a game with N non-terminal positions and m actions for each player in each position. In particular, both algorithms have doubly-exponential complexity. Even when the game given as input has only one non-terminal position, we prove an exponential lower bound on the worst case number of iterations needed to provide non-trivial approximations.
Keywords
Concurrent reachability games Value iteration Strategy iteration Analysis of algorithmsNotes
Acknowledgements
First and foremost, we would like to thank Uri Zwick for extremely helpful discussions and Kousha Etessami for being instrumental for starting this research. We would also like to thank Vladimir V. Podolskii for helpful discussions. A preliminary version of this paper [10] appeared in the proceeings of CSR’11.
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