Before revision: In recent decades, in developed economies, slack on the product and labor markets has fluctuated a lot over the business cycle, while inflation has been very stable. At the same time, these economies have been prone to enter long-lasting liquidity traps with stable positive inflation and high unemployment. Motivated by these observations, this paper develops a simple policy-oriented business-cycle model in which (1) fluctuations in aggregate demand and supply lead to fluctuations in slack but not in inflation;
After revision: This paper develops a new model of business cycles. The model is economical in that it is solved with an aggregate demand-aggregate supply diagram, and the effects of shocks and policies are obtained by comparative statics. The model builds on two unconventional assumptions. First, producers and consumers meet through a matching function. Thus, the model features unemployment, which fluctuates in response to aggregate demand and supply lead to fluctuations in slack but not in inflation;