Research Repository

On Interim Envy-Free Allocation Lotteries

Caragiannis, Ioannis and Kanellopoulos, Panagiotis and Kyropoulou, Maria (2021) On Interim Envy-Free Allocation Lotteries. In: 22nd ACM Conference on Economics and Computation, 2021-07-18 - 2021-07-23, Budapest, Hungary.

[img]
Preview
Text
On_Interim_Envy_Free_Allocation_Lotteries.pdf - Accepted Version

Download (660kB) | Preview

Abstract

With very few exceptions, recent research in fair division has mostly focused on deterministic allocations. Deviating from this trend, we study the fairness notion of interim envy-freeness (iEF) for lotteries over allocations, which serves as a sweet spot between the too stringent notion of ex-post envy-freeness and the very weak notion of ex-ante envy-freeness. iEF is a natural generalization of envy-freeness to random allocations in the sense that a deterministic envy-free allocation is iEF (when viewed as a degenerate lottery). It is also certainly meaningful as it allows for a richer solution space, which includes solutions that are provably better than envy-freeness according to several criteria. Our analysis relates iEF to other fairness notions as well, and reveals tradeoffs between iEF and efficiency. Even though several of our results apply to general fair division problems, we are particularly interested in instances with equal numbers of agents and items where allocations are perfect matchings of the items to the agents. Envy-freeness can be trivially decided and (when it can be achieved, it) implies full efficiency in this setting. Although computing iEF allocations in matching allocation instances is considerably more challenging, we show how to compute them in polynomial time, while also maximizing several efficiency objectives. Our algorithms use the ellipsoid method for linear programming and efficient solutions to a novel variant of the bipartite matching problem as a separation oracle. We also study the extension of interim envy-freeness notion when payments to or from the agents are allowed. We present a series of results on two optimization problems, including a generalization of the classical rent division problem to random allocations using interim envy-freeness as the solution concept.

Item Type: Conference or Workshop Item (Paper)
Additional Information: Published proceedings: Proceedings of the 22nd ACM Conference on Economics and Computation
Divisions: Faculty of Science and Health
Faculty of Science and Health > Computer Science and Electronic Engineering, School of
SWORD Depositor: Elements
Depositing User: Elements
Date Deposited: 02 Jul 2021 09:34
Last Modified: 15 Jan 2022 01:37
URI: http://repository.essex.ac.uk/id/eprint/30538

Actions (login required)

View Item View Item