Two firms produce substitute goods of unknown quality. At each stage the firms set prices and a consumer with private information and unit demand buys from one of the firms. Both firms and consumers see the entire history of prices and purchases. Will such markets aggregate information? Will the...

This review presents the well-known notion of merging, introduced by Blackwell and Dubins, and its later generalizations. While the original concept of merging refers to all future events, the two new concepts, of weak and of almost weak merging, are concerned only with forecasting near-future...

A central result in the rational learning literature is that if the true measure is absolutely continuous with respect to the beliefs then, given enough data, the updated beliefs merge with the true distribution. In this paper, we show that, under absolute continuity, weak merging occurs fast...