,
Michael Kaufmann
,
Maximilian Pfister
Creative Commons Attribution 4.0 International license
A well-known conjecture, named after David W. Barnette, asserts that every 3-regular, 3-connected, bipartite, planar graph (for short, Barnette graph) is Hamiltonian. As another step towards addressing Barnette’s conjecture positively, we show that every n-vertex Barnette graph admits a subhamiltonian cycle containing 5n/6 edges, improving upon the previous bound of 2n/3. Equivalently, every Barnette graph admits a 2-page book embedding in which at least 5n/6 consecutive vertex pairs along the spine are connected by edges. As a byproduct, we present a simple proof for a known result that guarantees the existence of Hamiltonian cycles in a certain subclass of Barnette graphs.
@InProceedings{bekos_et_al:LIPIcs.GD.2025.6,
author = {Bekos, Michael A. and Kaufmann, Michael and Pfister, Maximilian},
title = {{Approximating Barnette’s Conjecture}},
booktitle = {33rd International Symposium on Graph Drawing and Network Visualization (GD 2025)},
pages = {6:1--6:7},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-403-1},
ISSN = {1868-8969},
year = {2025},
volume = {357},
editor = {Dujmovi\'{c}, Vida and Montecchiani, Fabrizio},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.GD.2025.6},
URN = {urn:nbn:de:0030-drops-249927},
doi = {10.4230/LIPIcs.GD.2025.6},
annote = {Keywords: Barnette’s Conjecture, Subhamiltonicity, Book embeddings}
}