Building on the Ramsey-de Finetti idea of event exchangeability, we derive a characterization of probabilistic sophistication without requiring any of the various versions of monotonicity, continuity, or comparative likelihood assumptions imposed by Savage (1954), Machina and Schmeidler (1992),...

For economies with one private good and one public good, the author discusses social choice functions satisfying the following requirements: strategy-proofness--representing true preferences is a dominant strategy; symmetry--two agents having the same preference pay equal cost...