Abstract:This paper studies a form of advertising—keyword auction,which is widely used by search engines in recent years.In practice,how to set reserve prices for each keyword is a difficult problem.This paper adopts a divisible single-object auction to model the selling mechanism of the advertising and obtains a mathematical equation about optimal reserve price for search engine.The conclusion generalizes a classic result given by Riley and Samuelson and can be used in practice of search engine directly...