English

Finding perfect matchings in bridgeless cubic multigraphs without dynamic (2-)connectivity

Data Structures and Algorithms 2024-05-08 v1 Discrete Mathematics

Abstract

Petersen's theorem, one of the earliest results in graph theory, states that any bridgeless cubic multigraph contains a perfect matching. While the original proof was neither constructive nor algorithmic, Biedl, Bose, Demaine, and Lubiw [J. Algorithms 38(1)] showed how to implement a later constructive proof by Frink in O(nlog4n)\mathcal{O}(n\log^{4}n) time using a fully dynamic 2-edge-connectivity structure. Then, Diks and Sta\'nczyk [SOFSEM 2010] described a faster approach that only needs a fully dynamic connectivity structure and works in O(nlog2n)\mathcal{O}(n\log^{2}n) time. Both algorithms, while reasonable simple, utilize non-trivial (2-edge-)connectivity structures. We show that this is not necessary, and in fact a structure for maintaining a dynamic tree, e.g. link-cut trees, suffices to obtain a simple O(nlogn)\mathcal{O}(n\log n) time algorithm.

Keywords

Cite

@article{arxiv.2405.03856,
  title  = {Finding perfect matchings in bridgeless cubic multigraphs without dynamic (2-)connectivity},
  author = {Paweł Gawrychowski and Mateusz Wasylkiewicz},
  journal= {arXiv preprint arXiv:2405.03856},
  year   = {2024}
}
R2 v1 2026-06-28T16:18:43.548Z