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Agreeing to disagree type results under ambiguity

Published:12 July 2011Publication History

ABSTRACT

In this paper we show that unlike in Bayesian frameworks asymmetric information does matter and can explain differences in common knowledge decisions due to ambiguous character of agents' private information. Agents share a common, but-not-necessarily-additive, prior beliefs represented by capacities. It is shown that, if each agent's information partition is made up of unambiguous events in the sense of Nehring [12, Mat. Soc. Sci. 38, 197--213], then it is impossible that the agents disagree on their commonly known decisions, whatever these decisions are: whether posterior beliefs or conditional expectations. Conversely, an agreement on conditional expectations, but not on posterior beliefs, implies that agents' private information must consist of Nehring-unambiguous events. The results obtained allow to attribute the existence of a speculative trade to the presence of agents' diverse and ambiguous information.

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            TARK XIII: Proceedings of the 13th Conference on Theoretical Aspects of Rationality and Knowledge
            July 2011
            270 pages
            ISBN:9781450307079
            DOI:10.1145/2000378

            Copyright © 2011 ACM

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            Publication History

            • Published: 12 July 2011

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