This paper deals with the prevailing formal model for knowledge in contemporary economics, namely the state-space model introduced by Robert Aumann in 1976. In particular, the paper addresses the following question arising in this formalism: in order to state that an event is interactively or commonly known among a group of agents, do we need to assume that each of them knows how the information is imparted to the others? Aumann answered in the negative, but his arguments apply only to canonical, i.e., completely specified state spaces, while in most applications the state space is not canonical. This paper addresses the same question along original lines, demonstrating that the answer is negative for both canonical and not-canonical state spaces. Further, it shows that this result ensues from two counterintuitive properties held by knowledge in the state-space model, namely Substitutivity and Monotonicity.
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Paper provided by University of Turin in its series CESMEP Working Papers with number
200903.
References listed on IDEAS Please report citation or reference errors to , or , if you are the registered author of the cited work, log in to your RePEc Author Service profile, click on "citations" and make appropriate adjustments.:
Heifetz, Aviad & Meier, Martin & Schipper, Burkhard C., 2006.
"Interactive unawareness,"
Journal of Economic Theory,
Elsevier, vol. 130(1), pages 78-94, September.
[Downloadable!] (restricted)
Other versions:
Aviad Heifetz & Martin Meier & Burkhard C. Schipper, 2005.
"Interactive Unawareness,"
Discussion Papers
52, SFB/TR 15 Governance and the Efficiency of Economic Systems, Free University of Berlin, Humboldt University of Berlin, University of Bonn, University of Mannheim, University of Munich.
[Downloadable!]
HEIFETZ, Aviad & MEIER, Martin & SCHIPPER, Burkhard C., 2004.
"Interactive unawareness,"
CORE Discussion Papers
2004059, Université catholique de Louvain, Center for Operations Research and Econometrics (CORE).
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Aumann, Robert J. & Heifetz, Aviad, 2002.
"Incomplete information,"
Handbook of Game Theory with Economic Applications,
in: R.J. Aumann & S. Hart (ed.), Handbook of Game Theory with Economic Applications, edition 1, volume 3, chapter 43, pages 1665-1686
Elsevier.
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Aumann, Robert J. & Heifetz, Aviad, 2001.
"Incomplete Information,"
Working Papers
1124, California Institute of Technology, Division of the Humanities and Social Sciences.
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Geanakoplos, John, 1994.
"Common knowledge,"
Handbook of Game Theory with Economic Applications,
in: R.J. Aumann & S. Hart (ed.), Handbook of Game Theory with Economic Applications, edition 1, volume 2, chapter 40, pages 1437-1496
Elsevier.
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