We construct a utility-based model of fluctuations, with nominal rigidities and unemployment, and draw its implications for the unemployment-inflation tradeoff and for the conduct of monetary policy.lt;brgt;lt;brgt;We proceed in two steps. We first leave nominal rigidities aside. We show that,...

Historically, urban growth required enough development to grow and transport significant agricultural surpluses or a government effective enough to build an empire. But there has been an explosion of poor mega-cities over the last thirty years. A simple urban model illustrates that in closed...