,
Kristóf Huszár
Creative Commons Attribution 4.0 International license
Building on Whitney’s classical method of triangulating smooth manifolds, we show that every compact d-dimensional smooth manifold admits a triangulation with dual graph of twin-width at most d^O(d). In particular, it follows that every compact 3-manifold has a triangulation with dual graph of bounded twin-width. This is in sharp contrast to the case of treewidth, where for any natural number n there exists a closed 3-manifold such that every triangulation thereof has dual graph with treewidth at least n. To establish this result, we bound the twin-width of the dual graph of the d-skeleton of the second barycentric subdivision of the 2d-dimensional hypercubic honeycomb. We also show that every compact, piecewise-linear (hence smooth) d-dimensional manifold has triangulations where the dual graph has an arbitrarily large twin-width.
@InProceedings{bonnet_et_al:LIPIcs.SoCG.2025.23,
author = {Bonnet, \'{E}douard and Husz\'{a}r, Krist\'{o}f},
title = {{On the Twin-Width of Smooth Manifolds}},
booktitle = {41st International Symposium on Computational Geometry (SoCG 2025)},
pages = {23:1--23:16},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-370-6},
ISSN = {1868-8969},
year = {2025},
volume = {332},
editor = {Aichholzer, Oswin and Wang, Haitao},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.SoCG.2025.23},
URN = {urn:nbn:de:0030-drops-231752},
doi = {10.4230/LIPIcs.SoCG.2025.23},
annote = {Keywords: Smooth manifolds, triangulations, twin-width, Whitney embedding theorem, structural graph parameters, computational topology}
}