Bertrand, the Cournot Paradigm and the Theory of Perfect Competition
将伯特兰对古诺的经典批评扩展到一般均衡框架，构建了一个买卖双方同时报价报量的博弈模型，证明在至少有两个买家和两个卖家活跃交易的条件下，纯策略纳什均衡配置是竞争性的，即“两个就足以实现竞争”。
In this paper, we extend to a general equilibrium context Bertrand's classic critique of Cournot. We present a game-theoretic model of a pure exchange, monetary economy, in which buyers as well as sellers announce both quantities and prices. When buyers act strategically, the "Edgeworth nonexistence problem" is circumvented: under weak conditions, a pure strategy Nash equilibrium exists for this game. We make precise the Bertrand idea that when agents in a finite economy are permitted to compete-by-price the resulting allocations will be competitive. Specifically, the Nash equilibria for our game yield allocations that are "competitive" allocations for the underlying exchange economy, provided that there are at least two buyers and two sellers actively trading in every market. Under this characterization of strategic behaviour, then, "two is enough for competition."