Understanding Preferences: Demand Types, and the Existence of Equilibrium With Indivisibilities

• 成果类型: Article
• 署名作者: Baldwin, Elizabeth; Klemperer, Paul
• 署名单位: University of Oxford; University of Oxford
• 刊物名称: ECONOMETRICA
• ISSN/ISSBN: 0012-9682
• DOI: 10.3982/ECTA13693
• 发表日期: 2019
• 页码: 867-932
• 关键词: competitive-equilibrium; Discrete convexity; gross substitutes; Walrasian equilibrium; UNIMODULAR SYSTEMS; volume; DECOMPOSITION; algorithm; auction; GOODS

摘要

An Equivalence Theorem between geometric structures and utility functions allows new methods for understanding preferences. Our classification of valuations into Demand Types incorporates existing definitions (substitutes, complements, strong substitutes, etc.) and permits new ones. Our Unimodularity Theorem generalizes previous results about when competitive equilibrium exists for any set of agents whose valuations are all of a demand type. Contrary to popular belief, equilibrium is guaranteed for more classes of purely-complements than of purely-substitutes, preferences. Our Intersection Count Theorem checks equilibrium existence for combinations of agents with specific valuations by counting the intersection points of geometric objects. Applications include matching and coalition-formation, and the Product-Mix Auction introduced by the Bank of England in response to the financial crisis.