We present a new condition on beliefs that guarantee the Bayesian implementability of all efficient social decision rules. We show that this condition is easy to verify and is both more interpretable and more general than the conditions that are found in the literature. We also study conditions...

We propose a comprehensive concept of oligopolistic equilibrium, allowing for a parametrized continuum of competition regimes, with each firm setting simultaneously both its price and its quantity and facing two constraints: one relative to its share ofthe market, the other relative to the size...

In a pure exchange economy we propose a general equilibrium concept under imperfect competition, the "Cournotian Monopolistic Competition Equilibrium", and compare it to the Cournot-Walras and the Monopolistic Competition concepts. The advantage of the proposed concept is to simplify the...

Our goal is to describe the state of the art on Bayesian mechanisms when utility is transferable and only balanced transfers are admissible. New results will be proved along the way, but they will be integrated to the overall picture. We first study a condition on the information structure of...