In a world of endogenous fertility, where the number of descendants is an integral part of the economic allocation, the traditional concept of Pareto-optimality cannot be applied any longer: the number of individuals to be present on earth may vary between any two allocations we wish to compare....

This paper deals with the role of bubbles, having the same meaning as Ponzi games, for implementing efficient growth paths in a closed economy overlapping generations model. It is shown that the well-known arbitrage condition for bubbles, namely that they must yield the same return in...