Product Line Decisions and the Coase Conjecture
证明当耐用品垄断者同时销售与之需求相关的非耐用品时，科斯猜想不成立；非耐用品互补或替代会降低耐用品引入市场的速度，且耐用品价格不会收敛到边际成本。
We show that the Coase conjecture does not hold when a durable-goods monopolist also sells nondurable goods that are demand related to the durable. The presence of nondurable complements or substitutes reduces the rate at which the monopolist introduces the durable into the market. The price of the durable does not converge to marginal cost. We analyze the incentives of a monopolist to extend his product line to a durable or a nondurable. Most significantly, the profit from adding a durable to the product line disappears as the time between offers becomes short. We study the effects of entry into markets for nondurables and their implications for merger policy.