Unawareness, Beliefs and Speculative Trade

We define a generalized state-space model with interactive unawareness and probabilistic beliefs. Such models are desirable for potential applications of asymmetric unawareness. We compare unawareness with probability zero belief. Applying our unawareness belief structures, we show that the common prior assumption is too weak to rule out speculative trade in all states. Yet, we prove a generalized ""No-trade"" theorem according to which there can not be common certainty of strict preference to trade. Moreover, we show a generalization of the ""No-agreeing-to-disagree"" theorem.unawareness, awareness, zero probability, type-space, common prior, agreement, speculative trade, interactive epistemology

Unawareness, Beliefs, and Speculative Trade

We define a generalized state-space model with interactive unawareness and probabilistic beliefs. Such models are desirable for potential applications of asymmetric unawareness. Applying our unawareness belief structures, we show that the common prior assumption is too weak to rule out speculative trade in all states. Yet, we prove a generalized "No-speculative-trade" theorem according to which there can not be common certainty of strict preference to trade. Moreover, we prove a generalization of the "No-agreeing-to-disagree" theorem. Finally, we show the existence of a universal unawareness belief type space.Unawareness, awareness, common prior, agreement, speculative trade, universal type-space, interactive epistemology, inattention

Unawareness, Beliefs and Games

We define a generalized state-space model with interactive unawareness and probabilistic beliefs. Such models are desirable for many potential applications of asymmetric unawareness. We develop Bayesian games with unawareness, define equilibrium, and prove existence. We show how equilibria are extended naturally from lower to higher awareness levels and restricted from higher to lower awareness levels. We use our unawareness belief structure to show that the common prior assumption is too weak to rule out speculative trade in all states. Yet, we prove a generalized ``No-trade'' theorem according to which there can not be common certainty of strict preference to trade. Moreover, we show a generalization of the ``No-agreeing-to-disagree'' theorem.unawareness, awareness, type-space, Bayesian games, incomplete information, equilibrium, common prior, agreement, speculative trade, interactive epistemology

Unawareness, Beliefs and Games

We define a generalized state-space model with interactive unawareness and probabilistic beliefs. Such models are desirable for many potential applications of asymmetric unawareness. We develop Bayesian games with unawareness, define equilibrium, and prove existence. We show how equilibria are extended naturally from lower to higher awareness levels and restricted from higher to lower awareness levels. We use our unawareness belief structure to show that the common prior assumption is too weak to rule out speculative trade in all states. Yet, we prove a generalized “No-trade†theorem according to which there can not be common certainty of strict preference to trade. Moreover, we show a generalization of the “No-agreeing-to-disagree†theorem.unawareness; awareness; type-space; Bayesian games; incomplete information; equilibrium; common prior; agreement; speculative trade; interactive epistemology

Unawareness, Beliefs and Games

We define a generalized state-space model with interactive unawareness and probabilistic beliefs. Such models are desirable for many potential applications of asymmetric unawareness. We develop Bayesian games with unawareness, define equilibrium, and prove existence. We show how equilibria are extended naturally from lower to higher awareness levels and restricted from higher to lower awareness levels. We use our unawareness belief structure to show that the common prior assumption is too weak to rule out speculative trade in all states. Yet, we prove a generalized “No-trade” theorem according to which there can not be common certainty of strict preference to trade. Moreover, we show a generalization of the “No-agreeing-to-disagree” theorem

Speculative Trade and the Value of Public Information

In environments with expected utility, it has long been established that speculative trade cannot occur (Milgrom and Stokey [1982]), and that the value of public information is negative in economies with risk-sharing and no aggregate uncertainty (Hirshleifer [1971], Schlee [2001]). We show that these results are still true even if we relax expected utility, so that either Dynamic Consistency (DC) or Consequentialism is violated. We characterise no speculative trade in terms of a weakening of DC and find that Consequentialism is not required. Moreover, we show that a weakening of both DC and Consequentialism is sufficient for the value of public information to be negative. We therefore generalise these important results for convex preferences which contain several classes of ambiguity averse preferences

Standard State Space Models of Unawareness

The impossibility theorem of Dekel, Lipman and Rustichini has been thought to demonstrate that standard state-space models cannot be used to represent unawareness. We first show that Dekel, Lipman and Rustichini do not establish this claim. We then distinguish three notions of awareness, and argue that although one of them may not be adequately modeled using standard state spaces, there is no reason to think that standard state spaces cannot provide models of the other two notions. In fact, standard space models of these forms of awareness are attractively simple. They allow us to prove completeness and decidability results with ease, to carry over standard techniques from decision theory, and to add propositional quantifiers straightforwardly

Speculative Trade under Unawareness: The Infinite Case

We generalize the ``No-speculative-trade" theorem for finite unawareness belief structures in Heifetz, Meier, and Schipper (2013) to the infinite case.Awareness, unawareness, speculation, trade, agreement, common prior, common certainty

Speculative Trade under Unawareness: The Infinite Case

We generalize the "No-trade" theorem for finite unawareness belief structures in Heifetz, Meier, and Schipper (2009) to the infinite case.Awareness; unawareness; speculation; trade; agreement; common prior; common certainty

Preference-Dependent Unawareness

Morris (1996, 1997) introduced preference-based definitions of knowledge of belief in standard state-space structures. This paper extends this preference-based approach to unawareness structures (Heifetz, Meier, and Schipper, 2006, 2008). By defining unawareness and knowledge in terms of preferences over acts in unawareness structures and showing their equivalence to the epistemic notions of unawareness and knowledge, we try to build a bridge between decision theory and epistemic logic. Unawareness of an event is behaviorally characterized as the event being null and its negation being null.Unawareness, awareness, knowledge, preferences, subjective expected utility theory, decision theory, null event