English

On connected subgraph arrangements

Combinatorics 2026-05-19 v2 Algebraic Topology

Abstract

Recently, Cuntz and K\"uhne introduced a particular class of hyperplane arrangements stemming from a given graph GG, so called connected subgraph arrangements AGA_G. In this note we strengthen some of the result from their work and prove new ones for members of this class. For instance, we show that aspherical members withing this class stem from a rather restricted set of graphs. Specifically, if AGA_G is an aspherical connected subgraph arrangement, then AGA_G is free with the unique possible exception when the underlying graph GG is the complete graph on 44 nodes.

Keywords

Cite

@article{arxiv.2502.18144,
  title  = {On connected subgraph arrangements},
  author = {Lorenzo Giordani and Tilman Möller and Paul Mücksch and Gerhard Roehrle},
  journal= {arXiv preprint arXiv:2502.18144},
  year   = {2026}
}

Comments

30 pages. v2. Various minor changes and grant information updates. Final version to appear in Beitr\"age zur Algebra und Geometrie / Contributions to Algebra and Geometry

R2 v1 2026-06-28T21:57:14.382Z