Innovation by Leaders
提出在位垄断者通过预先承诺研发投资来维持垄断的新解释，发现自由进入时在位者比外部人更有创新激励，并分析了创新规模内生和序列创新下的投资模式，最后应用于熊彼特增长模型。
A new rationale for the persistence of monopolies is based on a precommitment of the incumbent monopolist to invest in R&D. In a patent race, as long as entry is free, the Arrow effect disappears: the incumbent has more incentives to invest than any outsider. Paradoxically, a market with some persistence of monopoly is competitive, while one with continuous leap-frogging must hide some barriers to entry. When the size of innovations is endogenous, leaders invest in more radical innovations. If there is a sequence of innovations, cycling investment emerges. Finally, I apply the idea to a general equilibrium model of Schumpeterian growth with persistence of monopoly.