Self-fulfilling Optimism in a Trade-Friction Model of the Business Cycle
构建了一个简化的动态模型，研究贸易摩擦经济中自我实现的销售预期如何决定经济收敛于哪个稳态，并发现资产价值（如股市）领先于经济活动。
Models of economic activity with frictions in coordinating trading have been shown to be capable of generating multiple steady states. (Peter Diamond, 1982, is the pioneering work; see my 1987a paper for a general discussion.) Less work has been done on out-of-steady-state dynamics in such models, which would enable us to examine what sort of fluctuations these models may generate. The absence of dynamics leaves open the question of which steady state the economy will reach, as well as whether the comovements of key variables resemble what is observed over the cycle. In my earlier paper (1987b), I presented a model combining search and aggregate demand approaches to unemployment to show how spillovers between product and labor markets could yield multiple equilibria. Here, a highly simplified dynamic model based on this work is presented, in which (self-fulfilling) sales expectations determine to which steady state the economy converges. These expectations are summarized by the asset values of firms which are producing output relative to those that are not. Two types of dynamic paths leading to stationary solutions can arise. The first is a saddle path. In addition, for certain parameter values, stable limit cycles emerge. Interestingly, over this cycle, asset values of firms (which one could interpret as stock market values) lead economic activity. I. Model Setup