We explore the applicability of coresets - a small subset of the input dataset that approximates a predefined set of queries - to the 1-center problem in 𝓁₁ spaces. This approach could potentially extend to solving the 1-center problem in related metric spaces, and has implications for streaming and dynamic algorithms. We show that in 𝓁₁, unlike in Euclidean space, even weak coresets exhibit exponential dependency on the underlying dimension. Moreover, while inputs with a unique optimal center admit better bounds, they are not dimension independent. We then relax the guarantee of the coreset further, to merely approximate the value (optimal cost of 1-center), and obtain a dimension-independent coreset for every desired accuracy ε > 0. Finally, we discuss the broader implications of our findings to related metric spaces, and show explicit implications to Jaccard and Kendall’s tau distances.
@InProceedings{carmel_et_al:LIPIcs.ITCS.2025.28, author = {Carmel, Amir and Guo, Chengzhi and Jiang, Shaofeng H.-C. and Krauthgamer, Robert}, title = {{Coresets for 1-Center in 𝓁₁ Metrics}}, booktitle = {16th Innovations in Theoretical Computer Science Conference (ITCS 2025)}, pages = {28:1--28:20}, series = {Leibniz International Proceedings in Informatics (LIPIcs)}, ISBN = {978-3-95977-361-4}, ISSN = {1868-8969}, year = {2025}, volume = {325}, editor = {Meka, Raghu}, publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik}, address = {Dagstuhl, Germany}, URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ITCS.2025.28}, URN = {urn:nbn:de:0030-drops-226566}, doi = {10.4230/LIPIcs.ITCS.2025.28}, annote = {Keywords: clustering, k-center, minimum enclosing balls, coresets, 𝓁₁ norm, Kendall’s tau, Jaccard metric} }
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