We consider robust virtual implementation, where robustness is the requirement that implementation succeed in all type spaces consistent with a given payoff type space as well as with a given space of first-order beliefs about the other agents’ payoff types. This last bit, which constitutes...

Decision makers lacking crucial specialist know-how often consult with better informed but biased experts. In our model the decision maker's choice problem is binary and her preferred option depends on the state of the world unknown to her. The expert observes the state and sends a report to the...

In many markets, homogenous goods and services are sold both by large global frms and small local frms. Surprisingly, the large frms charge, often substantially, higher prices. Examples include hotels, airlines, and coffee shops. This paper provides a parsimonious model that can account for...