This paper introduces a numerical method for solving concave continuous state dynamic programming problems which is based on a pair of polyhedral approximations of concave functions. The method is globally convergent and produces computable upper and lower bounds on the value function which can...

Recent research has found that the dynamic properties of the New Keynesian model are unorthodox when the nominal interest rate is zero. Improvements in technology and reductions in the labor tax rate lower economic activity and the size of the government purchase output multiplier is very large....