Single-Crossing Differences in Convex Environments
研究了在凸环境中（如彩票、商品束、消费流）偏好具有单交叉差异（SCD）的效用函数集合，证明无序SCD是区间选择比较静态的充要条件，并应用于廉价谈话、观察学习和集体选择。
Abstract An agent’s preferences depend on an ordered parameter or type. We characterize the set of utility functions with single-crossing differences (SCD) in convex environments. These include preferences over lotteries, both in expected utility and rank-dependent utility frameworks, and preferences over bundles of goods and over consumption streams. Our notion of SCD does not presume an order on the choice space. This unordered SCD is necessary and sufficient for “interval choice” comparative statics. We present applications to cheap talk, observational learning, and collective choice, showing how convex environments arise in these problems and how SCD/interval choice are useful. Methodologically, our main characterization stems from a result on linear aggregations of single-crossing functions.