Maximum List r-Colorable Induced Subgraphs in $$kP_3$$-Free Graphs
We show that, for every fixed positive integers r and k, Max-Weight List r-Colorable Induced Subgraph admits a polynomial-time algorithm on $$kP_3$$ -free graphs. This problem is a common generalization of Max-Weight Independent Set, Odd Cycle Transversal and List r-Coloring, among others. Our result has several consequences. First, it implies that, for every fixed $$r \ge 5$$ , assuming $$\textsf{P}\ne \textsf{NP}$$ , Max-Weight List r-Colorable Induced Subgraph is polynomial-time solvable on H-free graphs if and only if H is an induced subgraph of either $$kP_3$$ or $$P_5+kP_1$$ , for some $$k \ge 1$$ . Second, it makes considerable progress toward a complexity dichotomy for Odd Cycle Transversal on H-free graphs, allowing to answer a question of Agrawal, Lima, Lokshtanov, Rzążewski, Saurabh, and Sharma [ACM Trans. Algorithms 2025]. Third, it gives a short and self-contained proof of the known result of Chudnovsky, Hajebi, and Spirkl [Combinatorica 2024] that List r-Coloring on $$kP_3$$ -free graphs is polynomial-time solvable for every fixed r and k. We also consider two natural distance-d generalizations of Max-Weight Independent Set and List r-Coloring and provide polynomial-time algorithms on $$kP_3$$ -free graphs for every fixed integers r, k, and $$d \ge 6$$ .
Authors
- Esther Galby (ORCID: https://orcid.org/0009-0004-5398-2770)
- Andrea Munaro (ORCID: https://orcid.org/0000-0003-1509-8832)
- Amir Nikabadi (ORCID: https://orcid.org/0009-0002-1446-1935)
- Paloma T. Lima (ORCID: https://orcid.org/0000-0001-9304-4536)
Institutions
- University of Parma (IT)
- Chalmers University of Technology (SE)
- IT University of Copenhagen (DK)
- University of Gothenburg (SE)
Publication Details
- Journal
- Algorithmica
- Published
- 2026-10-05
- DOI
- https://doi.org/10.1007/s00453-026-01410-7
- Primary Topic
- Advanced Graph Theory Research
- Type
- article
- Field-Weighted Citation Impact
- 0.00