This paper provides an extension of general equilibrium theory that incorporates the actions of individuals both as demanders and suppliers of goods and as members of firms, schools, social groups, and contractual relationships. The central notion of the paper is a group: a collection of...

We present a theory of production that begins with an exogenously specified set of technologies, accessible to each potential firm. The technologies used in equilibrium are endogenous. Labor skills are differentiated, and the labor skills are acquired endogenously by workers, possibly by bearing...