October 2001 <p> Suppose a large economy with individual risk is modeled by a continuum of pairwise exchangeable random variables (i.i.d., in particular). Then the relevant stochastic process is jointly measurable only in degenerate cases. Yet in Monte Carlo simulation, the average of a large...</p>

March 2000 <p> Diamond and Mirrlees (1971) provide sufficient conditions for a second-best Pareto efficient allocation with linear commodity taxation to require efficient production when a finite set of consumers have continuous single-valued demand functions. This paper considers a continuum...</p>

September 1999 <p> Roberts' "weak neutrality" or "weak welfarism" theorem concerns Sen social welfare functionals which are defined on an unrestricted domain of utility function profiles and satisfy independence of irrelevant alternatives, the Pareto condition, and a form of weak continuity....</p>

August 1999 <p> For economies with a fixed finite set of traders, few results characterize Walrasian equilibria by their social choice properties. Pareto efficient allocations typically require lump-sum transfers. Other characterizations based on the core or strategyproofness apply only when, as in...</p>

February 1998 <p> In smooth exchange economies with a continuum of agents, any Walrasian mechanism is Pareto efficient, individually rational, anonymous, and strategy-proof.  Barberà and Jackson's (1995) results imply that no such efficient mechanism is the limit of resource-balanced,...</p>

March 1997 <p> Arrow's ``impossibility'' and similar classical theorems are usually proved for an unrestricted domain of preference profiles. Recent work extends Arrow's theorem to various restricted but ``saturating'' domains of privately oriented, continuous, (strictly) convex, and (strictly)...</p>

August 1997 <p> The standard decision theories of Savage and of Anscombe and Aumann both postulate that the domain of consequences is state independent. But this hypothesis makes no sense when, for instance, there is a risk of death or serious injury. The paper considers one possible way of...</p>

Latest revision: September 1998. Previous versions appeared under the titles "On Proving Gains from Trade and Migration," and "On the Contrast between Policies toward Trade and Migration." <p> Would unrestricted "economic" migration enhance the potential gains from free trade? First, with free...</p>

December 7, 1997 <p> To allow conditioning on counterfactual events, zero probabilities can be replaced by infinitesimal probabilities that range over a non-Archimedean ordered field. This paper considers a suitable minimal field that is a complete metric space. Axioms similar to those in Anscombe...</p>

Second version: November, 1995. <p>This paper partially extends the f-core equivalence theorem of Hammond, Kaneko and Wooders [7] for continuum economies with widespread externalities --- i.e., those over which each individual has negligible control. Externalities need not result directly from...</p>