Optimal monetary policy, endogenous sticky prices, and multiplicity of equilibria

"We analyze optimal monetary policy in an endogenous sticky price model. Similar models with exogenous sticky prices can deliver multiplicity of equilibria. Multiplicity of equilibria is a necessary condition for expectation traps to explain the variation across time and countries of inflation patterns. In our model's equilibrium, profit differentials between sticky price firms and flexible price firms are small. Also, the gain from revising prices for sticky prices firms is increasing in inflation. Depending on the distribution of price revision costs, if enough sticky price firms choose to revise their prices, the monetary authority's benefit from inflation is reduced to the point that the model has a unique, low inflation equilibrium"--Federal Reserve Bank of St. Louis web site.