Working Paper 356

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Equilibrium Existence in an Overlapping Generations Model With Altruistic Preferences

S. Rao Aiyagari

Revised July 1, 1987

We prove the existence of a competitive equilibrium in an overlapping generations model in which each generation has a preference ordering over its own and its descendents’ consumptions. The model is one of pure exchange with many goods in each period and two period lived generations. The bequest from one generation to the next is required to be non-negative and is endogenous. In equilibrium, some sequences of agents of successive generations may be continually “linked” by positive bequests and act as infinitely lived agents. Other sequences of agents may not be so linked and therefore behave as sequences of finite lived agents. We give three examples which illustrate the following points: (i) multiple equilibria may exist some of which resemble those of standard overlapping generations models, whereas in others some sequences of agents behave as if infinitely lived, (ii) multiple steady states of the above two types may exist in which the latter are unstable and the former are stable, and (iii) if agents have preferences given by discounted sums of utilities with different discount rates, then not all sequences of generations can be continually linked and hence behave as infinitely lived agents.

Published In: Journal of Economic Theory (Vol 47, Num 1, February 1989, pp. 130-152)

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