Atomic Cournotian traders may be Walrasian

• 成果类型: Article
• 署名作者: Codognato, Giulio; Ghosal, Sayantan; Tonin, Simone
• 署名单位: University of Udine; University of Glasgow
• 刊物名称: JOURNAL OF ECONOMIC THEORY
• ISSN/ISSBN: 0022-0531
• DOI: 10.1016/j.jet.2015.05.005
• 发表日期: 2015
• 页码: 1-14
• 关键词: Walras equilibrium; core; Cournot-Nash equilibrium; Mixed exchange economies

摘要

In a bilateral oligopoly, with large traders, represented as atoms, and small traders, represented by an atomless part, when is there a nonempty intersection between the sets of Walras and Cournot-Nash allocations? Using a two-commodity version of the Shapley window model, we show that a necessary and sufficient condition for a Cournot-Nash allocation to be a Walras allocation is that all atoms demand a null amount of one of the two commodities. We provide four examples which show that this characterization holds non-vacuously. When our condition fails to hold, we also confirm, through some examples, the result obtained by Okuno et al. (1980): small traders always have a negligible influence on prices, while the large traders keep their strategic power even when their behavior turns out to be Walrasian in the cooperative framework considered by Gabszewicz and Mertens (1971) and Shitovitz (1973). (C) 2015 Elsevier Inc. All rights reserved.