Nonatomic Economies and the Boundaries of Perfect Competition
区分了非原子性和厚市场作为完全竞争来源的不同，构建了一个非原子连续统交易者和差异化连续统商品的不完全竞争模型，发现非原子性下个体能影响价格且核心大于瓦尔拉斯分配集，而厚市场则不能。
The distinction between nonatomicity and thick markets as the source of perfect competition is examined. The authors construct a model of an imperfectly competitive economy with a nonatomic continuum of traders and a continuum of differentiated commodities for which Walrasian equilibria exist. The failure of perfect competition is identified in two ways: individuals can affect prices and the core is strictly larger than the set of Walrasian allocations. By contrast, it is shown that, when markets are physically or economically thick (or both), then individuals cannot typically affect prices and the core always coincides with the set of Walrasian allocations. Copyright 1994 by The Econometric Society.