I distinguish two types of macroeconomic models. The first type are top-down models in which some or all agents are capable of understanding the whole picture and use this superior information to determine their optimal plans. The second type are bottom-up models in which all agents experience...

This paper investigates a dynamic general equilibrium model with search. In particular, search externalities are reßected by an increasing returns to scale matching function, which may imply an indeterminate equilibrium. Hence, the model is capable to generate business ßuctuations, driven by...