论文标题
通过交替预测来解决零和游戏
Solving Zero-Sum Games through Alternating Projections
论文作者
论文摘要
在这项工作中,我们为一种天然的一阶迭代算法建立了近线性和强大的融合,该算法模拟了von Neumann在零和游戏中的交替投影方法。首先,我们为\ emph {不受约束的双线性游戏提供了乐观的梯度下降/上升(OGDA)(OGDA)的精确分析(OGDA)(OGDA)(OGDA)(OGDA),以\ emph {emph {emph {emph {emph {emph {emph {emph {emph {emph {emph {emph {emph {emph {emph {emph {emph)的多个方向延伸并增强了先前的结果。我们的表征基于我们为动力学得出的封闭形式解决方案,而我们的结果也揭示了几种令人惊讶的属性。确实,我们的主要算法贡献建立在我们发现的OGDA的几何特征上。也就是说,动力学的极限点是初始状态对吸引子空间的正交投影。 在此属性中,我们证明了自然类\ emph {约束}双线性游戏的平衡是无约束的固定点与相应的概率单纯性的相交。因此,我们采用OGDA实施交替的投影过程,将$ \ widetilde {\ Mathcal {o}}(\ log^2(1/ε))融合到$ε$ -APPAPPROXIMATE NASH平衡。我们的技术补充了最近追求最后一透明的工作,可确保最小值优化。最后,我们原则上说明了一个从任何游戏到假定的实例类别的微不足道的减少,而不会改变平衡空间。
In this work, we establish near-linear and strong convergence for a natural first-order iterative algorithm that simulates Von Neumann's Alternating Projections method in zero-sum games. First, we provide a precise analysis of Optimistic Gradient Descent/Ascent (OGDA) -- an optimistic variant of Gradient Descent/Ascent -- for \emph{unconstrained} bilinear games, extending and strengthening prior results along several directions. Our characterization is based on a closed-form solution we derive for the dynamics, while our results also reveal several surprising properties. Indeed, our main algorithmic contribution is founded on a geometric feature of OGDA we discovered; namely, the limit points of the dynamics are the orthogonal projection of the initial state to the space of attractors. Motivated by this property, we show that the equilibria for a natural class of \emph{constrained} bilinear games are the intersection of the unconstrained stationary points with the corresponding probability simplexes. Thus, we employ OGDA to implement an Alternating Projections procedure, converging to an $ε$-approximate Nash equilibrium in $\widetilde{\mathcal{O}}(\log^2(1/ε))$ iterations. Our techniques supplement the recent work in pursuing last-iterate guarantees in min-max optimization. Finally, we illustrate an -- in principle -- trivial reduction from any game to the assumed class of instances, without altering the space of equilibria.