Uniqueness of an equilibrium in infinite-horizon economies subject to taxes and externalities

This paper verifies the uniqueness of an equilibrium for a class of stochas tic infinite-horizon economies with capital that are subject to distortiona ry taxes or externalities. The proof develops the property of concavity Tor a nonlinear monotone operator whose fixed points correspond to equilibria. As the underlying monotone operator has been useful for establishing the e xistence of an equilibrium. and for computing an equilibrium, this approach also brings under one roof the study of existence. uniqueness. and approxi mation of an equilibrium in distorted economies. Journal of Economic Litera ture Classification Numbers. C60, H20. (C) 2000 Academic Press.