,
Jonathan Rollin
,
Torben Scheele
Creative Commons Attribution 4.0 International license
A graph is k-matching-planar if it admits a drawing in the plane such that, for every edge e, the edges crossing e contain no matching of size greater than k. The class of k-matching-planar graphs generalizes other beyond-planar graph classes, such as k-planar and fan-planar graphs. In a 2-layer drawing of a bipartite graph, the vertices of the two bipartition classes are placed on two parallel horizontal lines and edges are drawn as straight-line segments between them. We prove that every graph with a 2-layer k-matching-planar drawing has pathwidth at most 2k+1. Moreover, for every k ≥ 0, we construct a graph with a 2-layer k-matching-planar drawing whose pathwidth is 3⌊k/2⌋ + 1. On the algorithmic side, we consider the one-sided recognition problem where a fixed embedding of the vertices on one side is given. We show that this problem is NP-hard. On the other hand, we prove that the problem is fixed-parameter tractable with respect to k. Finally, we prove that the two-sided variant cannot be approximated within any constant factor in polynomial time unless P = NP.
@InProceedings{odak_et_al:LIPIcs.GD.2026.15,
author = {Odak, Saeed and Rollin, Jonathan and Scheele, Torben},
title = {{On 2-Layer k-Matching-Planar Graphs}},
booktitle = {34th International Symposium on Graph Drawing and Network Visualization (GD 2026)},
pages = {15:1--15:16},
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.2026.15},
URN = {urn:nbn:de:0030-drops-279108},
doi = {10.4230/LIPIcs.GD.2026.15},
annote = {Keywords: pathwidth, k-matching-planar graph, 2-layer drawings, NP-hardness, k-planar graph, one-sided graph drawing}
}