We model the optimal behaviour of a multiproduct monopolist investing both in process and in product innovation in a dynamic setting. Product innovation reduces the degree of substitutability between any two varieties. First, we find that R&D efforts increase in both directions as the number of...

In markets where product quality is important, more than one characteristic is usually necessary to define product quality and the amelioration of the goods characteristics is usually costly. Then, properties of production technologies, in particular if they exhibit economies or diseconomies of...

The issue of technical progress under uncertainty is nested into the debate on vertical integration vs outsourcing, to show that, in general, the former is preferable to the latter in terms of both expected profits and technological efficiency. It is then shown that there exist (i) an optimal...

This paper studies the optimal non linear income tax of couples. We build a general unitary model of labor supply and allow multidimensional heterogeneity in a discrete type framework. We concentrate our analysis on the resulting intra-family labor allocation of labor supplies and show that this...

This paper provides a unified treatment of externalities associated with fertility and human capital accumulation as they relate to pension systems. It considers as overlapping generations model in which every generation consists of high earners and low earners with the proportion of types being...

This paper shows that the design of education policy involves a potential conflict between welfare and social mobility. We consider a setting in which social mobility is maximized under the least elitist public education system, whereas welfare maximization calls for the most elitist system. We...

When accidental bequests signal otherwise unobservable individual characteristics such as productivity and longevity, the tax administration should partition the population into two groups: One consisting of people who do not receive an inheritance and the other of those who do. The first tagged...

We consider a two-period model. In the first period, individuals consume two goods: one is sinful and the other is not. The sin good brings pleasure but has a detrimental effect on second period health and individuals tend to underestimate this effect. In the second period, individuals can...

This paper studies the design of a nonlinear social security scheme in a society where individuals differ in two respects: productivity and degree of myopia. Myopic individuals may not save enough" for their retirement because their myopic self" emerges when labor supply and savings decisions...

This paper shows that the combination of habit formation - present consumption creating additional consumption needs in the future - and myopia may explain why some retirees are forced to unretire, i.e., unexpectedly return to work. It also shows that when myopia about habit formation leads to...