Information Update as Social Choice
Johan van Benthem

Abstract:
Information update and the resulting belief revision may be
viewed as a process of merging plausibility or preference
relations coming from different sources. In this note, first 
presented at the Dynamic Logic Workshop in Montréal June 2007,
we show how 'priority product update' in the sense of Baltag
& Smets can be characterized precisely in terms of reasonable 
postulates of 'social choice' between such sources. The result
uses ideas from Andréka, Ryan & Schobbens on preference merge,
and our somewhat radical view here is that agents are dynamic 
societies consisting of all inputs they received over time.