We fully characterize the preferences relations that can be represented by a utility. Representation is equivalent to the condition that preferences do not have too many "jumps". A characterization of preferences that can be represented by a continuous utility follows trivially from our...

We prove that the English auction (with bidders that need not be ex ante identical and may have interdependent valuations) has an efficient ex post equilibrium. We establish this result for environments where it has not been previously obtained. We also prove two versions of the...

We consider preference relations over information that are monotone: more information is preferred to less. We prove that, if a preference relation on information about an uncountable set of states of nature is monotone, then it is not representable by a utility function.

We consider preference relations over information that are monotone: more information is preferred to less. We prove that, if a preference relation on information about an uncountable set of states of nature is monotone, then it is not representable by a utility function.

We prove that the English auction (with bidders that need not be ex ante identical and may have interdependent valuations) has an efficient ex post equilibrium. We establish this result for environments where it has not been previously obtained. We also prove two versions of the...

This paper formalizes the relation between comparative statics and the out-of-equilibrium explanation for how a system evolves after a change in parameters.

The empirical evidence presented in this paper casts serious doubts on the by now widely accepted "stylized factes" of the exchange rate based stabilization programs (ERBS) as they are stated in Kiguel and Liviatan (1992) and in vegh (1992).