Advanced seminar in Economics - Yves Sprumont (Université de Montréal)
Strategy-proof Choice of Acts
Wednesday 21 March 2018 (11h00 - 12h30) - Extranef - 109
This work examines collective decision-making under uncertainty. We model
uncertain social prospects as acts mapping states of nature to (social) outcomes.
A social choice function (or SCF) assigns an act to every pro le of subjective
expected utility preferences over acts. A SCF is strategyproof if no agent ever
has an incentive to misrepresent her beliefs about the states of nature or her
valuation of the outcomes; it is ex-post efficient if the act selected at any given
preference pro le picks a Pareto-efficient outcome in every state of nature.
We offer a complete characterization of all strategyproof and ex-post efficient
SCFs. The chosen act must pick the most preferred outcome of some (possibly
different) agent in every state of nature. The set of states in which an agent's
top outcome is selected may vary with the reported belief pro le; it is the union
of all states assigned to her by a collection of constant, bilaterally dictatorial,
or bilaterally consensual assignment rules.