Essential Interest-Bearing Money
在Lagos和Wright的模型中研究最优货币政策，发现一类激励可行的政策能提高福利，这类政策必然包含非负通胀率和严格正的名义利率，且存在实现最优配置的激励可行政策。
I examine optimal monetary policy in a Lagos and Wright [A unified framework for monetary theory and policy analysis, J. Polit. Econ. 113 (2005) 463-484] model where trade is centralized and all exchange is voluntary. I identify a class of incentivefeasible policies that improve welfare beyond what is achievable with zero intervention. Any policy in this class necessarily entails a non-negative inflation rate and a strictly positive nominal interest rate. Despite the absence of a lump-sum tax instrument, there exists an incentive-feasible policy that implements the first-best allocation.