Compromise by"multimatum"

2026-01-29

AI Summary

This study addresses the problem of social choice between two agents in an infinite policy space by proposing an efficient compromise rule grounded in cardinalized common preferences. The work introduces a novel “multimatum” mechanism, wherein agents alternately propose sets of alternatives for the other to choose from. This mechanism extends alternating-offer bargaining games to the domain of set selection and fully implements the compromise solution in subgame perfect Nash equilibrium. Integrating tools from game-theoretic equilibrium analysis, cardinal preference representation, and mechanism design theory, the approach demonstrates broad applicability and effectiveness across diverse domains, including political economy, modeling of altruistic preferences, and facility location problems.

Technology Category

• Multiagent Systems: Mechanism Design
• Game Theory and Economic Paradigms: Mechanism Design
• Knowledge Representation and Reasoning: Preferences

Application Category

• Economics, Online Markets and Human Computation: Incentives in network design for Web infrastructures and ecosystems
• User Modeling, Personalization and Recommendation: Attacks and countermeasures in recommendation systems
• Security and Privacy: Large-scale security measurements

Abstract

We propose a solution and a mechanism for two-agent social choice problems with large (infinite) policy spaces. Our solution is an efficient compromise rule between the two agents, built on a common cardinalization of their preferences. Our mechanism, the multimatum, has the two players alternate in proposing sets of alternatives from which the other must choose. Our main result shows that the multimatum fully implements our compromise solution in subgame perfect Nash equilibrium. We demonstrate the power and versatility of this approach through applications to political economy, other-regarding preferences, and facility location.

Problem

• social choice
• compromise
• infinite policy space
• two-agent
• mechanism design

Innovation

• multimatum
• compromise rule
• common cardinalization
• subgame perfect Nash equilibrium
• full implementation