Monopolistic Competition as a Foundation for Keynesian Macroeconomic Models

Abstract

A general equilibrium macroeconomic model based on monopolistic competition is presented. The model exhibits a traditional multiplier in the short run, but due to free entry, the multiplier disappears in the long run. By construction all agents are fully rational. The Keynesian results are a consequence of the assumption of monopolistic competition, which creates a divergence between optimal private behavior and optimal social behavior.