United for Change: Deliberative Coalition Formation to Change the Status Quo
Edith Elkind, Davide Grossi, Ehud Shapiro, Nimrod Talmon
TL;DR
This paper studies how to identify widely supported proposals by decentralized deliberation where agents form and reform coalitions around proposals in a metric space. It introduces a formal transition-system model with five coalition-formation operators and analyzes termination and success guarantees across diverse spaces, including Euclidean spaces, weighted trees, and $d$-dimensional hypercubes. The results reveal a hierarchy of sufficiency: simple transitions suffice in some spaces, while richer or multi-party compromise transitions are required in others, highlighting the role of the proposal space's geometry. The framework provides theoretical foundations for online deliberation platforms and pre-vote decision processes that aim to surface broadly beneficial proposals for formal voting.
Abstract
We study a setting in which a community wishes to identify a strongly supported proposal from a space of alternatives, in order to change the status quo. We describe a deliberation process in which agents dynamically form coalitions around proposals that they prefer over the status quo. We formulate conditions on the space of proposals and on the ways in which coalitions are formed that guarantee deliberation to succeed, that is, to terminate by identifying a proposal with the largest possible support. Our results provide theoretical foundations for the analysis of deliberative processes such as the ones that take place in online systems for democratic deliberation support.