theoretical-computer-science / Algorithmic game theory; stochastic games; complexity of NP and coNP problems

Quasipolynomial-time solution of simple stochastic and turn-based stochastic mean-payoff games

Claims a deterministic algorithm with 2O((log⁡(L+2))2)2^{O((\log(L+2))^2)} bit operations that outputs the set of vertices of nonnegative value in finite turn-based stochastic mean-payoff games with signed binary rewards and arbitrary rational chance probabilities, and hence decides the threshold-1/2 problem for Condon's simple stochastic games in deterministic quasipolynomial time. The proof chooses an explicit discount of polynomial bit length and finds the discounted fixed point by a recursive labeling procedure. It does NOT give a polynomial-time algorithm, and it decides the threshold set rather than outputting values or strategies in the stated theorem.

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theoretical-computer-scienceOct 5, 2026Significance 44/100Registry: unreviewed

Quasipolynomial-time solution of simple stochastic and turn-based stochastic mean-payoff games

Prior state unknown→proved

Claims a deterministic algorithm with 2O((log⁡(L+2))2)2^{O((\log(L+2))^2)} bit operations that outputs the set of vertices of nonnegative value in finite turn-based stochastic mean-payoff games with signed binary rewards and arbitrary rational chance probabilities, and hence decides the threshold-1/2 problem for Condon's simple stochastic games in deterministic quasipolynomial time. The proof chooses an explicit discount of polyn…

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Claims a deterministic algorithm with 2O((log⁡(L+2))2)2^{O((\log(L+2))^2)} bit operations that outputs the set of vertices of nonnegative value in finite turn-based stochastic mean-payoff games with signed binary rewards and arbitrary rational chance probabilities, and hence decides the threshold-1/2 problem for Condon's simple stochastic games in deterministic quasipolynomial time. The proof chooses an explicit discount of polynomial bit length and finds the discounted fixed point by a recursive labeling procedure. It does NOT give a polynomial-time algorithm, and it decides the threshold set rather than outputting values or strategies in the stated theorem.

Claims a deterministic algorithm with 2O((log⁡(L+2))2)2^{O((\log(L+2))^2)} bit operations that outputs the set of vertices of nonnegative value in finite turn-based stochastic mean-payoff games with signed binary rewards and arbitrary rational chance probabilities, and hence decides the threshold-1/2 problem for Condon's simple stochastic games in deterministic quasipolynomial time. The proof chooses an explicit discount of polynomial bit length and finds the discounted fixed point by a recursive labeling procedure. It does NOT give a polynomial-time algorithm, and it decides the threshold set rather than outputting values or strategies in the stated theorem.

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