 This concept of equity does not need any other information than individual ordinal preferences. It is not welfarist, in the sense that from utility data alone it is impossible to distinguish an envy-free allocation from an allocation with envy. Moreover, an envy-free allocation may be Pareto-indifferent (everyone is indifferent) to another allocation that has envy. On the other hand, this concept is strongly egalitarian, and it is quite natural to view it as capturing the idea of equality of resources (Dworkin 2000). When resources are multi-dimensional, for instance when there are several consumption goods, and when individual preferences are heterogeneous, it is not obvious to define equality of resources, but the no-envy criterion seems the best concept for this purpose. It guarantees that no individual will consider that another has a better bundle than his. It has been shown by Varian (1976) that, if preferences are sufficiently diverse and numerous (a continuum), then the competitive equilibrium with equal shares is the only Pareto-efficient and envy-free allocation.