1) The document discusses the New Classical approach to macroeconomics, which explains business cycles through real shocks like technology changes rather than nominal rigidities.
2) It examines extensions to the original real business cycle model, including variations to the utility function, indivisible labor, non-market activity, and changes to government spending, to better match empirical observations.
3) It also discusses optimal inflation policy using New Classical models, finding that even 2% inflation reduces steady-state consumption substantially, implying inflation should be kept very low.