The paper addresses the following question: how efficient is the market system in allocating resources if trade takes place at some prices $p$ that are not necessarily competitive? Even though there are many partial answers to this question, an answer that stands comparison to the rigor by which...

We analyze whether noncooperative collusive equilibria are harder to sustain when individual demand levels are not fixed but are able to fluctuate. To do this, we extend a Bertrand type model of price competition to allow for fluctuating market shares when prices are equal. We find that, the...

We consider the problem of determining a set of optimal tariffs for an agent in a network, who owns a subset of the arcs of the network, and who wishes to maximize his revenues on this subset from a set of clients that make use of the network.The general variant of this problem is NP-hard,...

We consider the well-known result of Arrow (1953) that the set of equilibria of an economy with complete markets coincides with the one of an economy with sequentially complete markets. We show by means of two examples that this results is problematic when there exist multiple equilibrium...

This paper presents a formal epistemic framework for dynamic games in which players, during the course of the game, may revise their beliefs about the opponents'' utility functions. We impose three key conditions upon the players'' beliefs: (a) throughout the game, every move by the opponent...

In this paper we analyze equilibria in competitive environments under constraints across players'' strategies. This means that the action taken by one player limits the possible choices of the other players. In this context the classical approach, Kakutani''s Fixed Point theorem, does not work....

We revisit n-player coordination games with Pareto-ranked Nash equilibria. The novelty is that we introduce fuzzy play and a matching device, where each player does not choose which pure strategy to play, but instead chooses a nonempty subset of his strategy set that he submits to the matching...