We model pay-as-you-go (PAYG) social security systems as the outcome of majority voting within a standard OLG model with production and an exogenous population growth rate. At each point in time individuals work, save, consume and invest by taking the social security policy as given. The latter...

We present a consistent pure-exchange general equilibrium model where agents may not foreseen all possible future contingencies. Even with nominal assets and complete asset markets, in this context an equilibrium may not exist without appropriate assumptions. An intrinsic feature of the model is...

In recent dynamic models of learning and evolution a rate of mutation is usually assumed to be fixed. In this paper we use an evolutionary model to examine how the outcome of the dynamic process depends on the rate of change. In particular we examine how the log run growth rate of the population...

In this paper we conclude the research initiated in Modica and Rustichini [6]. We claim here, as we did in that paper, that simple uncertainty is not an adequate model of a subject's ignorance, because a major component of it is the inability to give a complete description of the states of the...

Models with endogenous growth due to production externalities imply that per capita output is positively affected by the size of the labor force (which we interpret as the stock of human capital). In this framework we investigate the effects of labor migration between two countries in the...

This paper studies the problem of a monopoly who is uncertain about the demand it faces and learns about it over time through its pricing experience. The demand curve facing the monopoly is not constant - it changes over time in a Markovian fashion. We characterize the monopoly's optimal policy...

Conditional Expected Utility Theory (CEUT) provides an axiomatic foundation for a theory of decision under uncertainty which allows agents to choose which event in the state space will occur. Here we provide an alternative axiomatization of this situation. In this framework CEUT may be seen a...

This is the first of a sequence of two papers where we present a formal model of unawareness. We contrast unawareness with certainty and uncertainty. A subject is certain of something when he knows that thing; he is uncertain when he does not know it, but he knows he does not: he is consciously...