Abstract: | In continuum economies, widespread externalities are those over which each individual has negligible control. Nash-Walrasian equilibria with lump-sum transfers are defined, and their existence proved. They are then characterized by the property of “f-constrained Pareto efficiency” for finite coalitions. More general “private good” Nash-Walrasian equilibria are characterized as private-good constrained-Pareto efficient. Introducing complete Pigou taxes or subsidies leads to equilibria that are characterized by constrained efficiency and f-constrained efficiency for given levels of the widespread externalities. But full efficiency requires resolving the public-good problem of determining those aggregate externalities or, equivalently, of setting appropriate Pigou prices. |