In a competitive search setting, publishers strategically modify their documents in response to induced rankings so as to improve their future ranking. We present a novel game-theoretic analysis of a competitive search setting where search-results diversification is applied. Our analysis reveals an inherent tradeoff between corpus diversity and corpus stability, where the latter corresponds to an equilibrium in a game. We analyze two representative diversification methods and show that stability need not necessarily be reached, leaving the corpus to rapid changes due to ranking incentivized modifications of publishers. We then present a novel approach to devise diversification-based ranking functions that are guaranteed to lead to corpus stability.

翻译：在竞争性搜索环境中，发布者会策略性地修改其文档以响应诱导出的排名，从而改善其未来的排名。我们提出了一个新颖的博弈论分析，针对应用了搜索结果多样化的竞争性搜索场景。我们的分析揭示了语料库多样性与语料库稳定性之间的固有权衡，其中后者对应于博弈中的均衡。我们分析了两种有代表性的多样化方法，并表明稳定性不一定能够达成，导致语料库因发布者受排名激励的修改而快速变化。随后，我们提出了一种新的方法，基于多样化设计排名函数，以确保语料库的稳定性。