Proportional Budget Allocations: Towards a Systematization

TL;DR

This paper extends proportionality axioms from multi-winner voting to participatory budgeting, introducing new axioms, analyzing their relationships, and evaluating existing rules against these criteria.

Contribution

It systematically defines new proportionality axioms for participatory budgeting and analyzes their implications, advancing the theoretical framework of fair resource allocation.

Findings

New proportionality axioms for participatory budgeting

Logical relationships among axioms established

Evaluation of Phragmén and Rule X against new criteria

Abstract

We contribute to the programme of lifting proportionality axioms from the multi-winner voting setting to participatory budgeting. We define novel proportionality axioms for participatory budgeting and test them on known proportionality-driven rules such as Phragm\'en and Rule X. We investigate logical implications among old and new axioms and provide a systematic overview of proportionality criteria in participatory budgeting.