Voting by Committees under Constraints



1 Introduction

Many problems of social choice take the following form. There are n voters
and a set
K = {1,..., k} of objects. These objects may be bills considered by
a legislature, candidates to some set of positions, or the collection of char-
acteristics which distinguish a social alternative from another. The voters
must choose a subset of the set of objects.

Sometimes, any combination of objects is feasible: for example, if we
consider the election of candidates to join a club which is ready to admit as
many of them as the voters choose, or if we are modelling the global results
of a legislature, which may pass or reject any number of bills. It is for these
cases that Barberà, Sonnenschein, and Zhou (1991) provided characteriza-
tions of all voting procedures which are strategy-proof and respect voter’s
sovereignty (all subsets of object may be chosen) when voters’ preferences
are additively represent able, and also when these are separable. For both of
these restricted domains, voting by committees turns out to be the family of
all rules satisfying the above requirements. Rules in this class are defined by
a collection of families of winning coalitions, one for each object; agents vote
for sets of objects; to be elected, an object must get the vote of all members
of some coalition among those that are winning for that object.

Most often, though, some combinations of objects are not feasible, while
others are: if there are more candidates than positions to be filled, only sets of
size less than or equal to the available number of slots are feasible; if objects
are the characteristics of an alternative, some collections of characteristics
may be mutually incompatible, and others not. Our purpose in this paper is
to characterize the families of strategy-proof voting procedures when not all
possible subsets of objects are feasible, and voters’ preferences are separable
or additively represent able. Our main conclusions are the following. First:



More intriguing information

1. The Nobel Memorial Prize for Robert F. Engle
2. The name is absent
3. The name is absent
4. The name is absent
5. BEN CHOI & YANBING CHEN
6. Picture recognition in animals and humans
7. Ruptures in the probability scale. Calculation of ruptures’ values
8. The name is absent
9. Testing Panel Data Regression Models with Spatial Error Correlation
10. Moi individuel et moi cosmique Dans la pensee de Romain Rolland
11. Behaviour-based Knowledge Systems: An Epigenetic Path from Behaviour to Knowledge
12. Education and Development: The Issues and the Evidence
13. 09-01 "Resources, Rules and International Political Economy: The Politics of Development in the WTO"
14. Who runs the IFIs?
15. A Dynamic Model of Conflict and Cooperation
16. Cancer-related electronic support groups as navigation-aids: Overcoming geographic barriers
17. The geography of collaborative knowledge production: entropy techniques and results for the European Union
18. Impact of Ethanol Production on U.S. and Regional Gasoline Prices and On the Profitability of U.S. Oil Refinery Industry
19. Manufacturing Earnings and Cycles: New Evidence
20. Sectoral specialisation in the EU a macroeconomic perspective