Pareto-minimality in the jungle

Abstract

We consider the simplest version of a jungle economy à la Piccione-Rubinstein, wherein as many agents as goods are assumed, agents consume at most one indivisible good, and a transitive strong power relation exists. We first study the wilderness of jungle equilibria, i.e., whether they are Pareto-minimal (an allocation is Pareto-minimal if it is impossible to reduce the welfare of one agent without increasing the welfare of another). We show that jungle equilibria are not necessarily Pareto-minimal. We then study and characterize the set of Pareto-minimal jungle equilibria. Second, we tackle the case of equally powerful people, in contrast to the assumption that the power relation is asymetric. Assuming specifically a transitive weak power relation, we show that jungle equilibria exist, but that they are not always unique, nor Pareto-optimal. We also provide conditions under which those equilibria are Pareto-minimal.