Strategic interaction and dynamics under endogenous time preference

This paper presents a strategic growth model with endogenous time preference. Due to the potential lack of concavity and the differentiability of the value functions associated with each agent’s problem, we employ the theory of monotone comparative statics and supermodular games based on order and monotonicity properties on lattices. In particular, we provide the sufficient conditions of supermodularity for dynamic games with open-loop strategies based on two fundamental elements: the ability to order elements in the strategy space of the agents and the strategic complementarity which implies upward sloping best responses. The supermodular game structure of the model lets us provide the existence and the monotonicity results on the greatest and the least equilibria. We sharpen these results by showing the differentiability of the value function and the uniqueness of the best response correspondences almost everywhere and show that the stationary state Nash equilibria tend to be symmetric. Finally, we numerically analyze to what extent the strategic complementarity inherent in agents’ strategies can alter the convergence results that could have emerged under a single agent optimal growth model. In particular, we show that the initially rich can pull the poor out of the poverty trap even when sustaining a higher level of steady state capital stock for itself.     

Stochastic endogenous time preference

Preference for flexibility arises inherently in sequential decision making. However, a majority of the literature has limitations to capture a changing preference for flexibility across time in the sense that such an attitude is independent of past actions. This study incorporates the histories of past actions into an infinite-horizon extension of Dekel et al. (2001) and models a decision maker whose attitude toward flexibility evolves over time from the uncertainty of future time preference or discount factors. Moreover, we provide behavioral comparisons of the degree of patience across different histories and characterize the shift of subjective beliefs about discount factors in the sense of an increasing convex and concave stochastic order.     

能源、技术与经济增长——基于中国与印度的比较分析

本文在Romer(1990)内生经济增长模型的基础上,以加入能源因子和将技术因子与能源、劳动力相融合为特征,得到更贴近现实的反映经济增长的产出方程式。通过检验中国和印度1965~2004年间的实证数据,运用VAR模型、Johansen协整检验和向量误差修正模型(VECM)等方法,对两国的能源及技术与经济增长的长期关系和短期动态影响进行了比较分析。结果显示:长期中,加入技术变量的能源因素与经济增长的弹性关系,中国表现为负,而在印度为正;技术对于经济增长的总体贡献,印度高于中国。短期中,能源与技术因素的短期波动对中国的经济增长影响较强;而资本的短期波动对印度的经济增长影响较强。