I study an economy with sellers and buyers with unit supplies and unit demands. Both parties have valuations uniformly distributed on a unit interval. I quantify the inefficiency, compared to the Walrasian market, caused by a market where the agents meet randomly. There are several causes of inefficiency that I deal with separately. First, even if there is perfect information about valuations i...

Topological effects produce chaos in multiagent simulation and distributed computation. We explain this result by developing three themes concerning complex systems in the natural and social sciences: (i) Pragmatically, a system is complex when it is represented efficiently by different models at different scales. (ii) Nontrivial topology, identifiable as we scale towards the global, induces co...

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 va...

This paper explores five topics where Georg Simmel’s Philosophy of Money poses challenges for contemporary monetary scholarship. First, any microfoundations for macroeconomics would be erected upon catallactical and not choice-theoretic foundations. Second, money is a tool of thought and not just a veil. Third, Simmel points to a way to make sense of a claim that goes back at least to Richard C...

We propose a new solution concept to address the problem of sharing a surplus among the agents generating it. The problem is formulated in the preferences-endowments space. The solution is defined recursively, incorporating notions of consistency and fairness and relying on properties satisfied by the Shapley value for Transferable Utility (TU) games. We show a solution exists, and call it an O...

We propose a new solution concept to address the problem of sharing a surplus among the agents generating it. The problem is formulated in the preferences-endowments space. The solution is defined recursively, incorporating notions of consistency and fairness and relying on properties satisfied by the Shapley value for Transferable Utility (TU) games. We show a solution exists, and call it the ...

We characterize the dynamics of trading patterns and market composition when trade is bilateral, finding a trading partner is costly, prices are determined by bargaining, and preferences are private information. We show that equilibrium is inefficient and exhibits delay as sellers price discriminate between buyers with different values. As frictions vanish, transaction prices are asymptotically...

We investigate experimentally the economic effects of wage taxation to finance unemployment benefits for a closed economy and an international economy. The main findings are the following. (i) There is clear evidence of a vicious circle in the dynamic interaction between the wage tax and unemployment. (ii) In the short run employment is boosted by budget deficits. However, subsequent tax rate a...

In a matching model of firm formation with moral hazard, we characterize the equilibrium for economies with scarcity of capital and study the effects of redistributive taxation. We give necessary and sufficient conditions determining the equilibrium matching patterns, payoffs and interest rate. These depend only on aggregate wealth and the median wealth relative to the active population, compar...

We show that in almost every economy with separable externalities, every competitive equilibrium can be Pareto improved by a package of anonymous commodity taxes that causes prices to adjust and markets to reclear at different levels of individual consumption. This constrained suboptimality of competitive allocations might provide a rationale for economic policy in economies with externalities....