For many centuries, forms of Islamic charity such as zakat (i.e. "obligatory" alms) and waqf (i.e. endowment or philanthropic foundation) have proven to be essential tools for economic and human development. Both of these schemes aim to reduce income inequality and to encourage productive...

A firm chooses a price and the product information it discloses to a consumer whose tastes are privately known. We provide a necessary and sufficient condition on the match function for full disclosure to be the unique equilibrium outcome whatever the costs and prior beliefs about product and...

Afriat proved the equivalence of a variant of the strong axiom of revealed preference and the existence of a solution to a set of linear inequalities. From this solution he constructed a utility function rationalizing the choices of a competitive consumer. We extend Afriat's theorem to a class...

In 'The Methodology of Positive Economics' (1953), Milton Friedman linked the adoption of a falsificationist methodology to the rejection of monopolistic competition as a valid assumption, thus elaborating a point made earlier by George Stigler in 'Monopolistic Competition in Retrospect' (1949)....

We provide a discipline for beliefs formation through a model of subjective beliefs, in which agents hold incorrect but strategic beliefs. More precisely, we consider beliefs as a strategic variable that agents can manipulate to maximize their utility from trade. Our framework is therefore an...

We study an economywhere intermediaries compete over contracts in a nonexclusive insurance market affected by moral hazard. In this context, we show that, contrarily to what is commonly believed, market equilibria may fail to be efficient even if the planner is not allowed to enforce...

L’ouverture des économies ne s’est pas, dans tous les cas, accompagnée d’une intensification spontanée de la concurrence. Dans certains secteurs, l'ouverture commerciale a sans doute favorisé la concentration où l’apparition de nouveaux monopoles ou duopoles mondiaux. Loin...

We analyze markets where insurers are better informed about risk than consumers. We show that even competitive markets may result in insufficient information revelation and inefficient insurance coverage. This explains why certain risky consumers remain uninsured and why certain market segments...