Ruling Out Multiplicity and Indeterminacy: The Role of Heterogeneity
指出，代表性代理人模型夸大了外部规模经济导致均衡多重性和不确定性的重要性，因为异质性具有稳定作用。通过两部门模型证明，足够的生产率异质性可确保均衡唯一和全局稳定。
It is well known that economies of scale that are external to the individual decision makers can lead to self-fulfilling prophecies and the multiplicity or even indeterminacy of equilibrium. We argue that the importance of this source of multiplicity and indeterminacy is overstated in representative agent models, as they ignore the potential stabilizing effect of heterogeneity. We illustrate this in a version of Matsuyama's (1991) two-sector model with increasing returns to scale. Two main results are shown. First, sufficient homogeneity with respect to individual productivity leads to the instability and non-uniqueness of a given stationary state and the indeterminacy of the corresponding stationary state equilibrium. Second, sufficient heterogeneity leads to the global saddle-path stability and the uniqueness of a given stationary state and the global uniqueness of equilibrium.