,
Csaba D. Tóth
Creative Commons Attribution 4.0 International license
For n points in the plane and an ε > 0, we construct a (1+ε)-spanner with O(n/ε) edges in which every edge has Õ(1/ε³) crossings, hence the total number of crossings is Õ(n/ε⁴), furthermore the ratio between the lengths of any two crossing edges is O(1/ε²). Our spanner construction substantially improves on the previous upper bound for the number of crossings in a (1+ε)-spanner, and it is the first spanner construction that ensures O(1) crossings per edge for any constant ε > 0. In contrast, we construct: n points in the plane for which every (1+ε)-spanner has Ω(n/ε³) crossings, n points for which every (1+ε)-spanner has an edge with Ω(1/ε^{5/2}) crossings, and 4 points for which every (1+ε)-spanner contains two crossing edges where one is Ω(1/ε) times longer than the other.
@InProceedings{luu_et_al:LIPIcs.GD.2026.36,
author = {Luu, Kelvin and T\'{o}th, Csaba D.},
title = {{Geometric (1+\epsilon)-Spanners with Few Crossings}},
booktitle = {34th International Symposium on Graph Drawing and Network Visualization (GD 2026)},
pages = {36:1--36:18},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-452-9},
ISSN = {1868-8969},
year = {2026},
volume = {396},
editor = {L\"{o}ffler, Maarten and Miksch, Silvia},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.GD.2026.36},
URN = {urn:nbn:de:0030-drops-279312},
doi = {10.4230/LIPIcs.GD.2026.36},
annote = {Keywords: crossings, spanners, empty region property}
}