2 research outputs found
Symmetric majority rules
In the standard arrovian framework and under the assumption that individual
preferences and social outcomes are linear orders on the set of alternatives,
we study the rules which satisfy suitable symmetries and obey the majority
principle. In particular, supposing that individuals and alternatives are
exogenously partitioned into subcommittees and subclasses, we provide necessary
and sufficient conditions for the existence of reversal symmetric majority
rules that are anonymous and neutral with respect to the considered partitions.
We also determine a general method for constructing and counting those rules
and we explicitly apply it to some simple cases
Breaking ties in collective decision making
Many classical social preference (multiwinner social choice) correspondences
are resolute only when two alternatives and an odd number of individuals are
considered. Thus, they generally admit several resolute refinements, each of
them naturally interpreted as a tie-breaking rule. In this paper we find out
conditions which make a social preference (multiwinner social choice)
correspondence admit a resolute refinement fulfilling suitable weak versions of
the anonymity and neutrality principles, as well as reversal symmetry (immunity
to the reversal bias)