Temporal Fair Division of Indivisible Goods with Scheduling

TL;DR

This paper explores the challenges of achieving temporal fairness in dividing indivisible goods over multiple rounds, introducing scheduling to improve fairness guarantees and identifying fundamental limits of such approaches.

Contribution

It characterizes the boundary between possibility and impossibility in temporal fair division, especially with scheduling, and provides approximation results under various settings.

Findings

A 1/2-approximation for TEFX in binary valuations with identical days and two agents.

Scheduling buffer of size at least n/2 enables TEF1 for identical days.

TEFX and TMMS remain largely impossible even with scheduling or restricted domains.

Abstract

We study temporal fair division, where agents receive goods over multiple rounds and cumulative fairness is required. We investigate Temporal Envy-Freeness Up to One Good (TEF1) and Up to Any Good (TEFX), its approximation $\alpha$-TEFX, and Temporal Maximin Share (TMMS). Motivated by known impossibilities in standard settings, we consider the model in various restricted settings and extend it by introducing scheduling. Our main contributions draw the boundary between possibility and impossibility. First, regarding temporal fair division without scheduling, we prove that while constant-factor $\alpha$-TEFX is impossible in general, a $1/2$-approximation is achievable for generalized binary valuations and identical days with two agents. Second, regarding temporal fair division with scheduling, we demonstrate that a scheduling buffer of size at least $n/2$ enables TEF1 for identical days. However, we establish that TEFX and TMMS remain largely impossible even with scheduling or restricted domains. These results highlight the inherent difficulty of strict temporal fairness and quantify the trade-offs required to achieve approximation guarantees.