Within an incomplete information framework (where the primitives are the individuals' belief hierarchies) we investigate the intersubjective implications of the assumption that it is common belief that no individual has any false beliefs (a key component of the Truth Axiom). We consider two...

When we make a non-trivial prediction about the future we select, among the conceivable future descriptions of the world, those that appear to us to be most likely. Within a branching-time framework we capture this by means of two binary relations, c and p. If t1 and t2 are different points in...

The logic of common belief does not always reflect the logic of individual beliefs. In particular, the Negative Introspection property fails at the common belief level, that is, it can happen that neither is A commonly believed nor is it common belief that A is not commonly believed. Indeed...

We provide an introduction to interactive belief systems from a qualitative and semantic point of view. Properties of belief hierarchies are formulated locally. Among the properties considered are "Common belief in no error" (which has been shown to have important game theoretic applications),...

Given an extensive form "G", we associate with every choice an atomic sentence and with every information set a set of well-formed formulas (wffs) of propositional calculus. The set of such wffs is denoted by [Gamma](G). Using the so-called topological semantics for propositional calculus (which...

The authors consider the case of a manufacturer who sells a homogeneous good to retailers who compe te in prices and "cum-sales" or "post-sales" services. They show that the optimal linear-price contract is inefficient from the point of view of the vertical structure and that simple forms of...

This survey is organized as follows. I. Introduction. II. The main issues. III. Negishi's model. IV. Objective demand in the Cournot-Nash framework. V. Objective demand in the Bertrand-Nash framework. VI. The assumption of quasi-concavity of the profit functions. VII. Compromises between the...

When we make a non-trivial prediction about the future we select, among the conceivable future descriptions of the world, those that appear to us to be most likely. Within a branching-time framework we capture this by means of two binary relations, c and p. If t1 and t2 are different points in...

This paper investigates the existence of oligopoly equilibria when firms arrive, through local price experiments, at a correct estimation of their demand curves in a neighborhood of a given statu s quo. The author provides sufficient conditions for the existence of a local Nash equilibrium,...