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Aris Filos-Ratsikas

13 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
2023

Explainable and Efficient Randomized Voting Rules

NeurIPS 2023poster

With a rapid growth in the deployment of AI tools for making critical decisions (or aiding humans in doing so), there is a growing demand to be able to explain to the stakeholders how these tools arrive at a decision. Consequently, voting is frequently used to make such decisions due to its inherent…

Cited by 6SourcePDFScholar
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
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
2021

Mechanism Design for Facility Location Problems: A Survey

IJCAI 2021poster

The study of approximate mechanism design for facility location has been in the center of research at the intersection of artificial intelligence and economics for the last decade, largely due to its practical importance in various domains, such as social planning and clustering. At a high level, t…

Cited by 102SourcePDFScholar
2020

Infochain: A Decentralized, Trustless and Transparent Oracle on Blockchain

IJCAI 2020poster

Blockchain based systems allow various kinds of financial transactions to be executed in a decentralized manner. However, these systems often rely on a trusted third party (oracle) to get correct information about the real-world events, which trigger the financial transactions. In this paper, we ide…

Cited by 0SourcePDFScholar
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
2020

Peer-Prediction in the Presence of Outcome Dependent Lying Incentives

IJCAI 2020poster

We derive conditions under which a peer-consistency mechanism can be used to elicit truthful data from non-trusted rational agents when an aggregate statistic of the collected data affects the amount of their incentives to lie. Furthermore, we discuss the relative saving that can be achieved by the…

Cited by 0SourcePDFScholar