A long-standing open problem in algorithmic game theory asks whether or not there is a polynomial time algorithm to compute a Nash equilibrium in a random bimatrix game. We study random win-lose games, where the entries of the $n\times n$ payoff matrices are independent and identically distributed (i.i.d.) Bernoulli random variables with parameter $p=p(n)$. We prove that, for nearly all values of the parameter $p=p(n)$, there is an expected polynomial-time algorithm to find a Nash equilibrium in a random win-lose game. More precisely, if $p\sim cn^{-a}$ for some parameters $a,c\ge 0$, then there is an expected polynomial-time algorithm whenever $a\not\in \{1/2, 1\}$. In addition, if $a = 1/2$ there is an efficient algorithm if either $c \le e^{-52} 2^{-8} $ or $c\ge 0.977$. If $a=1$, then there is an expected polynomial-time algorithm if either $c\le 0.3849$ or $c\ge \log^9 n$.
翻译:算法博弈论中长期存在的一个开放性问题,即是否存在多项式时间算法来计算随机双矩阵博弈中的纳什均衡。我们研究随机输赢博弈,其中 $n\times n$ 支付矩阵的条目是参数为 $p=p(n)$ 的独立同分布伯努利随机变量。我们证明,对于参数 $p=p(n)$ 的几乎所有取值,都存在一种期望多项式时间算法来寻找随机输赢博弈中的纳什均衡。更精确地说,如果 $p\sim cn^{-a}$,其中 $a,c\ge 0$ 为参数,那么只要 $a\not\in \{1/2, 1\}$,就存在期望多项式时间算法。此外,若 $a = 1/2$,则当 $c \le e^{-52} 2^{-8}$ 或 $c\ge 0.977$ 时存在高效算法。若 $a=1$,则当 $c\le 0.3849$ 或 $c\ge \log^9 n$ 时存在期望多项式时间算法。