Social and Behavioral Sciences Commons^™

Observability And Optimality, John Geanakoplos, Heracles M. Polemarchakis

Cowles Foundation Discussion Papers

Observability of an individual’s excess demand function for assets and commodities as all prices and revenue vary suffices in order to recover his von Neumann-Morgenstern utility function. This is generically the case, even when the asset market is incomplete and the cardinal utility indices state dependent, as long as there are at least two commodities traded in spot markets at each state of nature. On the contrary, if the response of individuals’ excess demand for assets as prices in spot commodity markets vary is not observable, recoverability fails when the asset market is incomplete. In particular, it is not possible …