English

Induced subgraphs and tree decompositions XVII. Anticomplete sets of large treewidth

Combinatorics 2025-11-25 v2

Abstract

Two sets X,YX, Y of vertices in a graph GG are "anticomplete" if XY=X\cap Y=\varnothing and there is no edge in GG with an end in XX and an end in YY. We prove that every graph GG of sufficiently large treewidth contains two anticomplete sets of vertices each inducing a subgraph of large treewidth unless GG contains, as an induced subgraph, a highly structured graph of large treewidth that is an obvious counterexample to this statement. These are: complete graphs, complete bipartite graphs and "interrupted ss-constellations." The latter is a slightly adjusted version of a well-known construction by Bonamy et al.

Keywords

Cite

@article{arxiv.2411.11842,
  title  = {Induced subgraphs and tree decompositions XVII. Anticomplete sets of large treewidth},
  author = {Maria Chudnovsky and Sepehr Hajebi and Sophie Spirkl},
  journal= {arXiv preprint arXiv:2411.11842},
  year   = {2025}
}

Comments

arXiv admin note: text overlap with arXiv:2410.16495