Stable Matching with Ties: Approximation Ratios and Learning

Fuente: arXiv
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Main Authors: Lin, Shiyun, Mauras, Simon, Merlis, Nadav, Perchet, Vianney
Format: Preprint
Published: 2024
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author Lin, Shiyun
Mauras, Simon
Merlis, Nadav
Perchet, Vianney
author_facet Lin, Shiyun
Mauras, Simon
Merlis, Nadav
Perchet, Vianney
contents We study matching markets with ties, where workers on one side of the market may have tied preferences over jobs, determined by their matching utilities. Unlike classical two-sided markets with strict preferences, no single stable matching exists that is utility-maximizing for all workers. To address this challenge, we introduce the \emph{Optimal Stable Share} (OSS)-ratio, which measures the ratio of a worker's maximum achievable utility in any stable matching to their utility in a given matching. We prove that distributions over only stable matchings can incur linear utility losses, i.e., an $Ω(N)$ OSS-ratio, where $N$ is the number of workers. To overcome this, we design an algorithm that efficiently computes a distribution over (possibly non-stable) matchings, achieving an asymptotically tight $O (\log N)$ OSS-ratio. When exact utilities are unknown, our second algorithm guarantees workers a logarithmic approximation of their optimal utility under bounded instability. Finally, we extend our offline approximation results to a bandit learning setting where utilities are only observed for matched pairs. In this setting, we consider worker-optimal stable regret, design an adaptive algorithm that smoothly interpolates between markets with strict preferences and those with statistical ties, and establish a lower bound revealing the fundamental trade-off between strict and tied preference regimes.
format Preprint
id arxiv_https___arxiv_org_abs_2411_03270
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Stable Matching with Ties: Approximation Ratios and Learning
Lin, Shiyun
Mauras, Simon
Merlis, Nadav
Perchet, Vianney
Computer Science and Game Theory
Machine Learning
We study matching markets with ties, where workers on one side of the market may have tied preferences over jobs, determined by their matching utilities. Unlike classical two-sided markets with strict preferences, no single stable matching exists that is utility-maximizing for all workers. To address this challenge, we introduce the \emph{Optimal Stable Share} (OSS)-ratio, which measures the ratio of a worker's maximum achievable utility in any stable matching to their utility in a given matching. We prove that distributions over only stable matchings can incur linear utility losses, i.e., an $Ω(N)$ OSS-ratio, where $N$ is the number of workers. To overcome this, we design an algorithm that efficiently computes a distribution over (possibly non-stable) matchings, achieving an asymptotically tight $O (\log N)$ OSS-ratio. When exact utilities are unknown, our second algorithm guarantees workers a logarithmic approximation of their optimal utility under bounded instability. Finally, we extend our offline approximation results to a bandit learning setting where utilities are only observed for matched pairs. In this setting, we consider worker-optimal stable regret, design an adaptive algorithm that smoothly interpolates between markets with strict preferences and those with statistical ties, and establish a lower bound revealing the fundamental trade-off between strict and tied preference regimes.
title Stable Matching with Ties: Approximation Ratios and Learning
topic Computer Science and Game Theory
Machine Learning
url https://arxiv.org/abs/2411.03270