,
Carsten Krollmann,
Daniel R. Schmidt
,
Melanie Schmidt
Creative Commons Attribution 4.0 International license
We study the k-center clustering problem under demographic fairness constraints, where the point set is partitioned into groups, and the aim is to compute clusters that exhibit a given group proportion. Previous work in this direction assumes that the entire point set already respects the desired proportions or uses relaxed notions of fairness. In this work, we propose a model that facilitates the creation of clusters that exactly match given target ratios, even when the input point set does not. We combine the well-known fair clustering model initiated by Chierichetti, Kumar, Lattanzi, and Vassilvitskii [Flavio Chierichetti et al., 2017] with the notion of outliers to obtain a practical combinatorial framework that provides constant-factor approximate solutions for all proportion settings from 1:1 for two groups to t₁:t₂:…:t_m for m ≥ 2 groups, where t₁,…,t_m are integers. We implement and evaluate our algorithms, compare different variants, and provide evidence of the practicability of this approach.
@InProceedings{arutyunova_et_al:LIPIcs.ESA.2026.23,
author = {Arutyunova, Anna and Fast, Irina and Hennes, Annika and Krollmann, Carsten and Schmidt, Daniel R. and Schmidt, Melanie},
title = {{Exact Ratio Preservation via Outliers for Fair k-Center Clustering}},
booktitle = {34th Annual European Symposium on Algorithms (ESA 2026)},
pages = {23:1--23:23},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-445-1},
ISSN = {1868-8969},
year = {2026},
volume = {388},
editor = {Bille, Philip and Pettie, Seth and Storandt, Sabine},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ESA.2026.23},
URN = {urn:nbn:de:0030-drops-271592},
doi = {10.4230/LIPIcs.ESA.2026.23},
annote = {Keywords: Fairness, k-center, approximation algorithms}
}
archived version
archived version