Models with generations, assets and public debt.

Summary This thesis is devoted to the modeling of the role of fixed assets, public debt and public capital in the framework of nested generation models à la diamond (1965). In the first part, after recalling the results of the literature on the role of "land" when it is used only as a factor of production, we study two particular issues when the services of the fixed asset are valued by both the firm and the households. We show that the existence of a fixed factor in the economy is an element in explaining the link between saving and investment in a small open economy. In a second step, we investigate which mode of land ownership maximizes the growth rate in a two-sector model in the manner of Rebelo (1991). We find the "traditional" result that the growth rate is maximized when land ownership is public. In the second part, we focus on the links between public capital and public debt. In a first model, we highlight the influence of the way public capital is financed on whether or not the economy is at the golden rule. In a second step, we study in the framework of an endogenous growth model the mode of financing and the proportion of public capital that maximizes the growth rate of the economy. The results depend on the elasticity of output with respect to private capital.