,
Robert Ganian
,
Mathis Rocton
Creative Commons Attribution 4.0 International license
The problem of whether and how one can compute the twin-width of a graph - along with an accompanying contraction sequence - lies at the forefront of the area of algorithmic model theory. While significant effort has been aimed at obtaining a fixed-parameter approximation for the problem when parameterized by twin-width, here we approach the question from a different perspective and consider whether one can obtain (near-)optimal contraction sequences under a larger parameterization, notably the feedback edge number k. As our main contributions, under this parameterization we obtain (1) a linear bikernel for the problem of either computing a 2-contraction sequence or determining that none exists and (2) an approximate fixed-parameter algorithm which computes an 𝓁-contraction sequence (for an arbitrary specified 𝓁) or determines that the twin-width of the input graph is at least 𝓁. These algorithmic results rely on newly obtained insights into the structure of optimal contraction sequences, and as a byproduct of these we also slightly tighten the bound on the twin-width of graphs with small feedback edge number.
@InProceedings{balaban_et_al:LIPIcs.STACS.2024.7,
author = {Balab\'{a}n, Jakub and Ganian, Robert and Rocton, Mathis},
title = {{Computing Twin-Width Parameterized by the Feedback Edge Number}},
booktitle = {41st International Symposium on Theoretical Aspects of Computer Science (STACS 2024)},
pages = {7:1--7:19},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-311-9},
ISSN = {1868-8969},
year = {2024},
volume = {289},
editor = {Beyersdorff, Olaf and Kant\'{e}, Mamadou Moustapha and Kupferman, Orna and Lokshtanov, Daniel},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.STACS.2024.7},
URN = {urn:nbn:de:0030-drops-197170},
doi = {10.4230/LIPIcs.STACS.2024.7},
annote = {Keywords: twin-width, parameterized complexity, kernelization, feedback edge number}
}