In this paper we compare two different approaches to modeling unawareness: the object-based approach of Board and Chung (2007) and the subjective-state-space approach of Heifetz, Meier and Schipper (2006).

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The goal of this paper is to construct a user-friendly model of unawareness. We start from an axiom system (in first-order modal logic) that enables us to express the following kinds of sentences: “the agent is not sure whether or not there is anything that he is unaware of”, and “I am not...

We show that for many classes of symmetric two-player games, the simple decision rule "imitate-the-best" can hardly be beaten by any other decision rule. We provide necessary and sufficient conditions for imitation to be unbeatable in the sense that, even against a very clever opponent,...

Heifetz, Meier and Schipper (2005) introduced a generalized state-space model that allows for non-trivial unawareness among several individuals and strong properties of knowledge. We show that this generalized state-space model arises naturally if states consist of maximally consistent sets of...

In the economic literature on market competition, firms are often modelled as single decision makers and the internal organization of the firm is neglected (unitary player assumption). However, as the literature on strategic delegation suggests, one can not generally expect that the behavior of...

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

We present a non-technical account of ambiguity in strategic games and show how it may be applied to economics and social sciences. Optimistic and pessimistic responses to ambiguity are formally modelled. We show that pessimism has the effect of increasing (decreasing) equilibrium prices under...

Internet experiments are a new and convenient way for reaching a large subject pool. Yet, providing incentives to subjects can be a tricky design issue. One cost effective and simple method is the publication of a high score (as in computer games). We test whether a high score provides adequate...