OLG模型中的多重均衡和经济效率——兼论政府在经济中的作用

Multiple Equilibrium and Economic Efficiency in OLG Model with Production: Recognize the Role of Government in the Economy

本文在一个具有生产部门的OLG模型中,在考虑政府具有公共资本(或债务)的情况下,分别在新古典生产函数和阿罗-罗默生产函数下,研究了经济的多重均衡和经济效率,并讨论了政府在经济中的作用。本文研究表明,在新古典生产函数下,经济存在两类均衡,一类是传统均衡,这时无政府公共资本(或债务);另一类是利率等于人口增长率的均衡,这时或存在公共资本,或存在公共债务。利率等于人口增长率的均衡是社会最优均衡,满足资本积累黄金法则;传统均衡在古典情形下是帕累托最优,但在萨缪尔森情形下不是帕累托最优。本文还在阿罗-罗默内生增长经济中讨论了经济的多重平衡增长路径,以及不同平衡增长路径的经济效率。论文分析表明,政府通过公共资本(或债务)介入经济能提高经济效率。

The paper analyzes competitive equilibrium and economic efficiency in an OLG model with production loans and public capital （or public debt ） , and we show that there are the same characters in our OLG model as in a pure exchange OLG model. Furthermore, this paper concludes that, in an OLG model with production loans and government public capital （ or public debt） , （ i ） there exist two kinds of steady state path, one is golden rule path in which the rate of interest equals the growth rate of population, and the other is a classical ＂balanced＂ path in which the public capital or public debt is zero; （ii） the golden rule path is always Pareto optimal and social optimal, but the classical ＂balanced＂ path is not always social optimal and even not Pareto optimal in Samuelson case; （iii） the golden rule program is globally stable in the classical case and the classical ＂balanced＂ program is globally stable in the Samuelson ease. Based the above results, this paper also discusses the role of the government in the economy.