Picking Sequences and Monotonicity in Weighted Fair Division
Picking Sequences and Monotonicity in Weighted Fair Division
Mithun Chakraborty, Ulrike Schmidt-Kraepelin, Warut Suksompong
Proceedings of the Thirtieth International Joint Conference on Artificial Intelligence
Main Track. Pages 82-88.
https://doi.org/10.24963/ijcai.2021/12
We study the problem of fairly allocating indivisible items to agents with different entitlements, which captures, for example, the distribution of ministries among political parties in a coalition government. Our focus is on picking sequences derived from common apportionment methods, including five traditional divisor methods and the quota method. We paint a complete picture of these methods in relation to known envy-freeness and proportionality relaxations for indivisible items as well as monotonicity properties with respect to the resource, population, and weights. In addition, we provide characterizations of picking sequences satisfying each of the fairness notions, and show that the well-studied maximum Nash welfare solution fails resource- and population-monotonicity even in the unweighted setting. Our results serve as an argument in favor of using picking sequences in weighted fair division problems.
Keywords:
Agent-based and Multi-agent Systems: Resource Allocation
Agent-based and Multi-agent Systems: Computational Social Choice