๐ค AI Summary
This study investigates the design of social choice rules that satisfy surjectivity and pairwise strategy-proofness in a public decision-making setting involving agents with single-peaked preferences alongside agents who are completely indifferentโi.e., indifferent across all levels of the public good, effectively abstaining. It introduces, for the first time, fully indifferent agents into the domain of single-peaked preferences, thereby constructing a hybrid preference framework. Employing an axiomatic approach from social choice theory, the paper fully characterizes the structure of target rules with a default option. The main contribution lies in establishing that, within this extended preference domain, surjectivity and pairwise strategy-proofness jointly provide an axiomatic characterization of such rules, offering a theoretical foundation for public decision mechanisms that accommodate abstention.
๐ Abstract
We study a public decision problem in which a finite society selects a public-good level from a closed interval. Agents either have single-peaked preferences or are completely indifferent over the interval; the latter capture abstention or a "none of the above" stance within the decision process. We study this augmented single-peaked domain. On this domain, we characterize the class of rules called target rules with a default. We show that onto-ness and pairwise strategy-proofness characterize this class of rules.