Abstract:
Multiwinner voting rules are methods agents can use to determine a social choice comprising more than one alternative. We discuss two types: Social Assignment Rules, including the Chamberlin-Courant rule, and Committee Selection Rules including approval voting. We give precise conditions for strategic voting to be possible for these rules, and a variant of each. In addition, for each type we give a class of strategyproof and non-dictatorial rules, showing that the Duggan-Schwartz theorem does not extend to all multiwinner rules.