Obviously Strategy-proof Choice of Social Acts

2026-05-28

AI Summary

This study investigates whether unanimous social choice functions can be implemented via obviously strategy-proof mechanisms within the social choice framework introduced by Bahel and Sprumont. Drawing on mechanism design theory and the notion of obvious strategy-proofness, the paper provides the first complete characterization of the class of unanimous social choice functions that admit such implementation. The central result establishes that a unanimous social choice function is implementable in an obviously strategy-proof manner if and only if it corresponds to a dictatorial rule. This finding not only delineates the precise boundary of feasible mechanisms under stringent incentive compatibility requirements but also underscores the unique role of dictatorship in ensuring robust truth-telling incentives.

Abstract

We study obviously strategy-proof implementation in the framework of social choice over acts introduced by Bahel and Sprumont (2020). We characterize the class of unanimous social choice functions that are implementable via obviously strategy-proof mechanisms. Our main result shows that a unanimous social choice function is obviously strategy-proof implementable if and only if it is dictatorial.

Problem

• obviously strategy-proof
• social choice
• implementation
• unanimous social choice functions
• dictatorial

Innovation

• obviously strategy-proof
• social choice over acts
• dictatorial
• unanimous social choice function
• mechanism design