English

Graphs with no long claws: An improved bound for the analog of the Gy\'{a}rf\'{a}s' path argument

Combinatorics 2025-01-24 v1 Discrete Mathematics Data Structures and Algorithms

Abstract

For a fixed integer t1t \geq 1, a (tt-)long claw, denoted St,t,tS_{t,t,t}, is the unique tree with three leaves, each at distance exactly tt from the vertex of degree three. Majewski et al. [ICALP 2022, ACM ToCT 2024] proved an analog of the Gy\'{a}rf\'{a}s' path argument for St,t,tS_{t,t,t}-free graphs: given an nn-vertex St,t,tS_{t,t,t}-free graph, one can delete neighborhoods of O(logn)\mathcal{O}(\log n) vertices so that the remainder admits an extended strip decomposition (an appropriate generalization of partition into connected components) into particles of multiplicatively smaller size. This statement has proven to be very useful in designing quasi-polynomial time algorithms for Maximum Weight Independent Set and related problems in St,t,tS_{t,t,t}-free graphs. In this work, we refine the argument of Majewski et al. and show that a constant number of neighborhoods suffice.

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Cite

@article{arxiv.2501.13907,
  title  = {Graphs with no long claws: An improved bound for the analog of the Gy\'{a}rf\'{a}s' path argument},
  author = {Romain Bourneuf and Jana Masaříková and Wojciech Nadara and Marcin Pilipczuk},
  journal= {arXiv preprint arXiv:2501.13907},
  year   = {2025}
}