Existence of a competitive equilibrium in a one sector growth model with heterogeneous agents and irreversible investment

International audience; Wr prove existence of a competitive equilibrium in a version of a Ramsey (one sector) model in which agents are heterogeneous and gross investment is constrained to be non negative. We do so by converting the infinite-dimensional fixed point problem tated in terms of prices and commodities into a finite-dimensional Negishi problem involving individual weights in a social value function. This method allows us to obtain detailed results concerning the properties of competitive eqilibria. Because of the simplicity of techniques utilized our approach is amenable to be adapted by practioners in analogous problems often studied in macroeconomics