Optimal growth models aim at explaining long run trends of growth under the strong assumption of full efficiency in the allocation of resources. As a result, the steady state time paths of the main economic aggregates reflect constant, exogenous or endogenous, growth. To introduce business...

New Keynesian models attempt to account for economic fluctuations under nominal rigidities without modelling unemployment. They struggle to generate observed output and inflation persistence. To address these issues, recent research embeds labour search with matching frictions in a New Keynesian...