Standard-Nutzungsbedingungen:Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden.Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen.Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, gelten abweichend von diesen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. Terms of use: Documents in Mai 1993Transition from a pay-as-you-go to a fully-funded pension system: The case of differing individuals and intragenerational fairness AbstractIn recent contributions to the theory of public pension systems it was argued that a Paretoimproving transition from an established unfunded pension system to a funded one is possible.This result is derived in an overlapping-generations model with identical individuals. In the present study an extended model, with differing individuals, of an intragenerationally fair unfunded pension scheme is introduced. Within this more realistic framework it is shown that, in general, a Pareto-improving transition to a funded system is not possible, because any instrument applied for the financing of pensions in the phase of transition involves intragenerational redistribution.

The Bass model, which is an effective forecasting tool for innovation diffusion based on large collections of empirical data, assumes an homogeneous diffusion process. We introduce a network structure into this model and we investigate numerically the dynamics in the case of networks with link density P (k) = c/k γ , where k = 1, . . . , N . The resulting curve of the total adoptions in time is qualitatively similar to the homogeneous Bass curve corresponding to a case with the same average number of connections. The peak of the adoptions, however, tends to occur earlier, particularly when γ and N are large (i.e., when there are few hubs with a large maximum number of connections). Most interestingly, the adoption curve of the hubs anticipates the total adoption curve in a predictable way, with peak times which can be, for instance when N = 100, between 10% and 60% of the total adoptions peak. This may allow to monitor the hubs for forecasting purposes. We also consider the case of networks with assortative and disassortative correlations and a case of inhomogeneous advertising where the publicity terms are "targeted" on the hubs while maintaining their total cost constant.

This work studies the impact of income inequality on the level of innovative activities in a model where innovations result in quality improvements. In contrast to the standard model of innovations and growth, the equilibrium outcome may be characterized by a situation where not only the quality leader but also producers of worse qualities are on the market. In that case the quality leader sells to the rich, whereas the producer of the second-best quality sells to the poor. In general, we find that a more equal distribution of income is favourable for innovation incentives. This is consistent with empirical evidence suggesting that countries with a more equal distribution of income have grown faster.

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This paper investigates the effect of adverse selection and price competition on the private annuity market in a model with two retirement periods. In this framework annuity companies can offer contracts with different payoffs over the periods of retirement. Varying the time structure of the payoffs affects annuity demand and welfare of individuals with low and high life expectancy in different ways. By this, annuity purchasers can be separated according to their survival probabilities. Our main finding is that a Nash-Cournot equilibrium may not exist; if one exists, it will be a separating equilibrium. On the other hand, even if a separating equilibrium does not exist, a Wilson pooling equilibrium exists