The main result of this paper characterizes voting by committees. There are n voters and K objects. Voters must choose a subset of K. Voting by committees is defined by one monotone family of winning coalitions for each object; an object is chosen if it is supported by one of its winning...

The authors consider the problem of allocating a bundle of commodities among a group of agents who are collectively entitled to them. It is proved that, for an atomless economy with possibly satiated preferences, any solution that is efficient, equitable, and consistent must select allocations...