,
Yuta Mishima
Creative Commons Attribution 4.0 International license
This paper introduces a new reconfiguration problem of matchings in a triangular grid graph. In this problem, we are given a nearly perfect matching in which each matching edge is labeled, and aim to transform it to a target matching by sliding edges one by one. This problem is motivated to investigate the solvability of a sliding-block puzzle called "Gourds" on a hexagonal grid board, introduced by Hamersma et al. [ISAAC 2020]. The main contribution of this paper is to prove that, if a triangular grid graph is factor-critical and has a vertex of degree 6, then any two matchings can be reconfigured to each other. Moreover, for a triangular grid graph (which may not have a degree-6 vertex), we present another sufficient condition using the local connectivity. Both of our results provide broad sufficient conditions for the solvability of the Gourds puzzle on a hexagonal grid board with holes, where Hamersma et al. left it as an open question.
@InProceedings{kakimura_et_al:LIPIcs.ISAAC.2024.43,
author = {Kakimura, Naonori and Mishima, Yuta},
title = {{Reconfiguration of Labeled Matchings in Triangular Grid Graphs}},
booktitle = {35th International Symposium on Algorithms and Computation (ISAAC 2024)},
pages = {43:1--43:16},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-354-6},
ISSN = {1868-8969},
year = {2024},
volume = {322},
editor = {Mestre, Juli\'{a}n and Wirth, Anthony},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ISAAC.2024.43},
URN = {urn:nbn:de:0030-drops-221709},
doi = {10.4230/LIPIcs.ISAAC.2024.43},
annote = {Keywords: combinatorial reconfiguration, matching, factor-critical graphs, sliding-block puzzles}
}