Antoine d'Autume

Endogenous growth in Arrow's Learning by Doing model

Although Arrows Learning by Doing model is recognized as a forerunner of recent models of endogenous growth, it seems that the virtues of Arrows approach are frequently overlooked. We show that endogenous growth is possible in the original Arrow framework and we examine how the analysis in terms of a vintage technology, with the intertemporal nature of the externality which it implies, differs from the one in the Romer (1986) paper.

The Zero discounting and maximin optimal paths in a simple model of global warming

Following Stollery (1998), we extend the Solow-- Dasgupta--Heal model to analyze the effects of global warming The rise of temperature is caused by the use of fossil resources so that the temperature level can be linked to the remaining stock of these resources. The rise of temperature affects both productivity and utility. We characterize optimal solutions for the maximin and zero-discounting cases and present closed form solutions for the case where the production and utility functions are Cobb-Douglas, and the temperature level is an exponential function of the remaining stock of resources. We show that a greater weight of temperature in intratemporal preferences or a larger intertemporal elasticity of substitution both lead to postpone resource use.

‘Transversality conditions’, budget constraints and the determinacy of a perfect foresight equilibrium in a monetary growth model

The purpose of this paper is to analyze the number of perfect foresight equilibria in a monetary model where the consumers behavior and the firms behavior are explicitly derived from an intertemporal optimization. We show that the relevant transversality conditions reduce to the satisfaction of the intertemporal budget constraint of the consumer, or alternatively of the government. The assumption of a separable utility function enables us to characterize completely the perfect foresight equilibria: their number is shown to depend both on the specification of the governments policy instruments and on the utility function.

Déséquilibre général et investissement

We analyze an intertemporal disequilibrium macroeconomic model under perfect foresight and with a fixed real wage. The focus is on investment behavior derived from an intertemporal optimization. The introduction of overtime work ensures the absence of discontinuities between regimes. This enables us to clarify the respective roles of the real wage level, of autonomous demand and of expectations in the determination of the level of output both in the short and in the long run.

La taxe carbone doit-elle être la même dans tous les pays ?

International differences in fuel taxation are huge, and may be justified by different local negative externalities that taxes must correct, as well as by different preferences for public spending. In this context, should a worldwide unique carbon tax be added to these local taxes to correct the global warming externality? We show that when lump-sum transfers between countries are allowed for, the carbon price must be the same in all countries. Nevertheless, if lump-sum transfers between governments are impossible to implement, international differentiation of the carbon price is the only way to take care of equity concerns.