Suchergebnisse

We study the properties of a GEI model with nominal assets, outside money (injected into the economy as in Magill and Quinzii), and multiple currencies. We analyze the existence of monetary equilibria and the structure of the equilibrium set under two different assumptions on the determination of the exchange rates. If currencies are perfect substitutes, equilibrium allocations are indeterminate and, generically, sunspot equilibria exist. Generically, given a nonsunspot equilibrium, there are Pareto improving (and Pareto worsening) sunspot equilibria associated with an increase in the volatility of the future exchange rates. We interpret this property as showing that, in general, there is no clear-cut effect on welfare of the excess volatility of exchange rates, even when due to purely extrinsic phenomena.

Abstract
We consider an economy where production may use labor of two different skill levels. Workers are heterogeneous and, by investing in education, self-select into one of the two skills. Ex-ante, when firms choose their investments in physical capital, they do not know the level of human capital prevailing in the labor market they will be active in. We prove existence and constrained inefficiency of competitive equilibria, which are always characterized by overeducation. An increase in total expected surplus can be obtained by shrinking, at the margin, the set of workers investing in high skills. This can be implemented by imposing taxes on the cost of investing in high skills or by imposing a progressive labor earning tax.

We consider a random matching model where heterogeneous agents choose optimally to invest time and real resources in education. Generically, there is a steady state equilibrium, where some agents, but not all of them, invest. Regular steady state equilibria are constrained inefficient in a strong sense. The Hosios (1990) condition is neither necessary, nor sufficient, for constrained efficiency. We also provide restrictions on the fundamentals sufficient to guarantee that equilibria are characterized by overeducation (or undereducation), present some results on their comparative statics properties, and discuss the nature of welfare improving policies. ; Im Rahmen eines Matching-Modells wird die optimale Investitionsentscheidung heterogener Agenten in Humankapital untersucht. Generisch existiert ein Gleichgewicht, in dem einige, aber nicht alle Agenten investieren. Reguläre Steady-State-Gleichgewichte sind im starken Sinne beschränkt ineffzient. Die Hosios-Bedingung ist für beschränkte Effzienz weder notwendig noch hinreichend. Weiter zeigen wir Restriktionen auf, die hinreichend sind für die Existenz eines Gleichgewichts, das durch Über- oder Unterinvestition in Bildung gekennzeichnet ist. Schließlich diskutieren wir komparativ-statische Eigenschaften des Modells sowie wohlfahrtssteigernde Politikmaßnahmen.

We consider a random matching model where heterogeneous agents choose optimally to invest time and real resources in education. Generically, there is a steady state equilibrium, where some agents, but not all of them, invest. Regular steady state equilibria are constrained inefficient in a strong sense. The Hosios (1990) condition is neither necessary, nor sufficient, for constrained efficiency. We also provide restrictions on the fundamentals sufficient to guarantee that equilibria are characterized by overeducation (or undereducation), present some results on their comparative statics properties, and discuss the nature of welfare improving policies.

We study a two-sector economy with investments in human and physical capital and imperfect labor markets. Human and physical capital are heterogeneous. Workers and firms endogenously select the sector they are active in, and choose the amount of their sector-specific investments in human and physical capital. To enter the high-skill sector, workers must pay a fixed cost that we interpret as direct cost of education. Given the distribution of the agents across sectors, at equilibrium, in each sector there is underinvestment in both human and physical capital, due to non-contractibility of investments. A second source of inefficiency is related to the self-selection of the agents into the two sectors. It typically induces too many workers to invest in education. Under suitable restrictions on the parameters, the joint effect of the two distortions is that equilibria are characterized by too many people investing too little effort in the high skill sector. We also analyze the welfare properties of equilibria and study the effects of several tax-subsidy policies on the total expected surplus.

"Im Rahmen eines Matching-Modells wird die optimale Investitionsentscheidung heterogener Agenten in Humankapital untersucht. Generisch existiert ein Gleichgewicht, in dem einige, aber nicht alle Agenten investieren. Reguläre Steady-State-Gleichgewichte sind im starken Sinne beschränkt ineffizient. Die Hosios-Bedingung ist für beschränkte Effizienz weder notwendig noch hinreichend. Weiter zeigen wir Restriktionen auf, die hinreichend sind für die Existenz eines Gleichgewichts, das durch Über- oder Unterinvestition in Bildung gekennzeichnet ist. Schliess- lich diskutieren wir komparativ-statische Eigenschaften des Modells sowie wohlfahrtssteigernde Politikmassnahmen." (Autorenreferat)