Monetary Neutrality with Sticky Prices and Free Entry
证明，在迪克西特-斯蒂格利茨偏好下，若企业自由进入且产品种类最优，即使价格固定，货币政策也是中性的；价格粘性仅当进入存在摩擦时才导致非中性。
Abstract Monetary policy is neutral even with fixed prices if free entry determines product variety optimally, as in Dixit and Stiglitz (1977). Entry substitutes for price flexibility in the welfare-based price index when individual prices are sticky. In response to aggregate demand expansions, the intensive (quantity produced of each good) and ex tensive (number of goods being produced) margins move in offsetting ways, leaving aggregate production unchanged. Price stickiness thus generates deviations from monetary neutrality only in conjunction with entry frictions: when variety is not optimally determined (preferences are not Dixit-Stiglitz) or when entry is subject to sunk costs and lags. Wage stickiness instead implies nonneutrality even in the frictionless-entry benchmark.