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>

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>

April 2000 <p> As is well known, a continuous parameter process with mutually independent random variables is not jointly measurable in the usual sense. This paper proposes using a natural ``one-way Fubini'' property that guarantees a unique meaningful solution to this joint measurability problem...</p>

May 1997 (Revised May 1998) <p> By definition, multilaterally strategy-proof mechanisms are immune to manipulation not only by individuals misrepresenting their preferences, but also by finite coalitions exchanging tradeable goods on the side. Continuum economies are defined in which both agents'...</p>

July 2000 <p> Marshallian consumer surplus (MCS) is generally an inaccurate measure of welfare change because it neglects income effects. Suppose these effects overturn the usual demand response to a price change. Then, the deadweight loss from a distortionary tax or subsidy has the wrong sign,...</p>