In this paper we axiomatically characterize two recursive procedures for defining a social group.The first procedure starts with the set of all individuals who define themselves as members of the social group, while the starting point of the second procedure is the set of all individuals who are...

A number of authors have proposed theories of efficiency wages to explain the behaviour of aggregate labor markets. According to these theories, firms do not adjust wages downwards despite available unemployed job seekers, because lower wages would induce hired workers to shirk more often, which...