Reserve Requirements and the Inflation Tax: Comment
评论Brock（1989）的模型，将劳动供给内生化，推广了其图1中等福利曲线的斜率表达式，对研究货币政策和通货膨胀的学者有参考价值。
In a recent article Brock (1989) considers inflationary Emance in an economy where money is demanded because it allows a representative agent to reduce the time spent on shopping in the goods market. Brock's model is characterized by an agent with preferences defined over consumption and leisure where currency and demand deposits impact on utility only indirectly through a time constraint. By holding additional money the agent can lower the quantity of time spent on shopping, and thus enjoy more consumption and leisure. Although Brock's model specifies an endogenous supply of labor in production, the derivations associated with his Figure 1 require the assumption of a fixed supply of labor in production. The purpose of this comment is to generalize some of the expressions obtained by Brock (especially the slope of the iso-welfare curves in Figure 1) to the case of an endogenous supply of labor by applying the envelope theorem to the model. In Brock's model, the agent's choice vatiables are functions of the nominal interest rate (i) and the reserare ratio (X), so that the indirect utility function can be written as follows: