Local Strategy Improvement for Parity Game Solving

Oliver Friedmann
(University of Munich)
Martin Lange
(University of Kassel)

The problem of solving a parity game is at the core of many problems in model checking, satisfiability checking and program synthesis. Some of the best algorithms for solving parity game are strategy improvement algorithms. These are global in nature since they require the entire parity game to be present at the beginning. This is a distinct disadvantage because in many applications one only needs to know which winning region a particular node belongs to, and a witnessing winning strategy may cover only a fractional part of the entire game graph.

We present a local strategy improvement algorithm which explores the game graph on-the-fly whilst performing the improvement steps. We also compare it empirically with existing global strategy improvement algorithms and the currently only other local algorithm for solving parity games. It turns out that local strategy improvement can outperform these others by several orders of magnitude.

In Angelo Montanari, Margherita Napoli and Mimmo Parente: Proceedings First Symposium on Games, Automata, Logic, and Formal Verification (GANDALF 2010), Minori (Amalfi Coast), Italy, 17-18th June 2010, Electronic Proceedings in Theoretical Computer Science 25, pp. 118–131.
Published: 9th June 2010.

ArXived at: http://dx.doi.org/10.4204/EPTCS.25.13 bibtex PDF

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