← Search

Alexandros A. Voudouris

14 accepted papers

2025

Optimal Metric Distortion for Matching on the Line

IJCAI 2025

We study the distortion of one-sided and two-sided matching problems on the line. In the one-sided case, n agents need to be matched to n items, and each agent's cost in a matching is their distance from the item they were matched to. We propose an algorithm that is provided only with ordinal inform

Cited by 0SourcePDFScholar
2024

Improved Metric Distortion via Threshold Approvals

AAAI 2024technical

We consider a social choice setting in which agents and alternatives are represented by points in a metric space, and the cost of an agent for an alternative is the distance between the corresponding points in the space. The goal is to choose a single alternative to (approximately) minimize the soci…

Cited by 7SourcePDFScholar
2022

Don't Roll the Dice, Ask Twice: The Two-Query Distortion of Matching Problems and Beyond

NeurIPS 2022accept

In most social choice settings, the participating agents express their preferences over the different alternatives in the form of linear orderings. While this clearly simplifies preference elicitation, it inevitably leads to poor performance with respect to optimizing a cardinal objective, such as t…

Cited by 14SourcePDFScholar
2022

Fair Division of Indivisible Goods: A Survey

IJCAI 2022poster

Allocating resources to individuals in a fair manner has been a topic of interest since the ancient times, with most of the early rigorous mathematical work on the problem focusing on infinitely divisible resources. Recently, there has been a surge of papers studying computational questions regardin…

Cited by 105SourcePDFScholar
2022

Heterogeneous Facility Location with Limited Resources

AAAI 2022technical

We initiate the study of the heterogeneous facility location problem with limited resources. We mainly focus on the fundamental case where a set of agents are positioned in the line segment [0,1] and have approval preferences over two available facilities. A mechanism takes as input the positions an…

Cited by 24SourcePDFScholar
2022

On Discrete Truthful Heterogeneous Two-Facility Location

IJCAI 2022poster

We revisit the discrete heterogeneous two-facility location problem, in which there is a set of agents that occupy nodes of a line graph, and have private approval preferences over two facilities. When the facilities are located at some nodes of the line, each agent derives a cost that is equal to h…

Cited by 19SourcePDFScholar
2021

A Few Queries Go a Long Way: Information-Distortion Tradeoffs in Matching

AAAI 2021technical

We consider the one-sided matching problem, where n agents have preferences over n items, and these preferences are induced by underlying cardinal valuation functions. The goal is to match every agent to a single item so as to maximize the social welfare. Most of the related literature, however, ass…

Cited by 33SourcePDFScholar
2021

Distortion in Social Choice Problems: The First 15 Years and Beyond

IJCAI 2021poster

The notion of distortion in social choice problems has been defined to measure the loss in efficiency---typically measured by the utilitarian social welfare, the sum of utilities of the participating agents---due to having access only to limited information about the preferences of the agents. We su…

Cited by 103SourcePDFScholar
2020

Maximum Nash Welfare and Other Stories About EFX

IJCAI 2020poster

We consider the classic problem of fairly allocating indivisible goods among agents with additive valuation functions and explore the connection between two prominent fairness notions: maximum Nash welfare (MNW) and envy-freeness up to any good (EFX). We establish that an MNW allocation is always EF…

Cited by 0SourcePDFScholar