Patent Height and Competition in Product Improvements
研究专利高度（即新颖性要求的严格程度）如何影响双寡头企业在产品改进中的竞争，发现低专利不影响市场均衡，中等专利可能使专利持有者受损，高专利则使其成为纯垄断者。
MERIT Research Memoranda can be ordered from the address below, or be obtained in electronic form (Postscript) by anonymous ftp at meritbbs.rulimburg.nl Revised Version, April 1994 The stringency of novelty requirements that patent offices and courts use in judging infringement issues and patentability of inventions defines the height of protection provided to a patentholder. In this paper the effects of patent height are studied in a duopoly where firms compete in product improvements. Minimal steps of improvements, determined by the height, limit the strategy space of competitors who want to invent around a patent. It is shown that low patents do not affect the natural market equilibrium. A patentholder can lose with medium patent heights, but he becomes a pure monopolist if patents are high. The nonpatentholder can gain with medium heights but is increasingly worse off with higher patents.