,
Nir Petruschka
Creative Commons Attribution 4.0 International license
The Nearest Neighbor Search (NNS) problem asks to design a data structure that preprocesses an n-point dataset X lying in a metric space β³, so that given a query point q β β³, one can quickly return a point of X minimizing the distance to q. The efficiency of such a data structure is evaluated primarily by the amount of space it uses and the time required to answer a query. We focus on the fast query-time regime, which is crucial for modern large-scale applications, where datasets are massive and queries must be processed online, and is often modeled by query time poly(d log n) when β³ is a d-dimensional normed space. Our main result is such a randomized data structure for NNS in π_p^d spaces, p > 2, that achieves p^{O(1) + log log p} approximation with fast query time and poly(dn) space. Our data structure improves, or is incomparable to, the state-of-the-art for the fast query-time regime from [Bartal and Gottlieb, TCS 2019] and [Krauthgamer, Petruschka and Sapir, FOCS 2025].
@InProceedings{krauthgamer_et_al:LIPIcs.SoCG.2026.66,
author = {Krauthgamer, Robert and Petruschka, Nir},
title = {{Fast Nearest Neighbor Search for π\underlinep Metrics}},
booktitle = {42nd International Symposium on Computational Geometry (SoCG 2026)},
pages = {66:1--66:9},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-418-5},
ISSN = {1868-8969},
year = {2026},
volume = {367},
editor = {Ahn, Hee-Kap and Hoffmann, Michael and Nayyeri, Amir},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SoCG.2026.66},
URN = {urn:nbn:de:0030-drops-258737},
doi = {10.4230/LIPIcs.SoCG.2026.66},
annote = {Keywords: Nearest neighbor search, metric embeddings, π\underlinep norm}
}