Competitive Market Mechanisms as Social Choice Procedures

A competitive market mechanism is a prominent example of a non-binary social choice rule, typically defined for a special class of economic environments in which each social state is an economic allocation of private goods, and individuals' preferences concern only their own personal consumption. This chapter begins by discussing which Pareto efficient allocations can be characterized as competitive equilibria with lump-sum transfers. It also discusses existence and characterization of such equilibria without lump-sum transfers. The second half of the chapter focuses on continuum economies, for which such characterization results are much more natural given that agents have negligible influence over equilibrium prices.

Competitive market mechanisms as social choice procedures

A competitive market mechanism is a prominent example of a non-binary social choice rule, typically defined for a special class of economic environments in which each social state is an economic allocation of private goods, and individuals' preferences concern only their own personal consumption. This chapter begins by discussing which Pareto efficient allocations can be characterized as competitive equilibria with lump-sum transfers. It also discusses existence and characterization of such equilibria without lump-sum transfers. The second half of the chapter focuses on continuum economies, for which such characterization results are much more natural given that agents have negligible influence over equilibrium prices

Equal Rights to Trade and Mediate

August 1999 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 continuum economies, agents cannot influence prices strategically. Or the results concern social choice with a variable number of agents. This paper considers allocations granting agents equal rights to choose net trade vectors within a convex cone and, in order to exclude autarky, an additional right to mediate mutually beneficial transactions. Under standard assumptions, these properties characterize Walrasian equilibria without transfers. JEL: Classifications: D63, D50