English

Relative Vertex Asphericity

Geometric Topology 2021-07-01 v2 Group Theory

Abstract

Diagrammatic reducibility DR and its generalization vertex asphericity VA are combinatorial tools developed for detecting asphericity of a 2-complex. Here we present tests for a relative version of VA that apply to pairs of 2-complexes (L,K)(L,K), where KK is a subcomplex of LL. We show that a relative weight test holds for injective labeled oriented trees, implying that they are VA and hence aspherical. This strengthens a result obtained by the authors in 2017 and simplifies the original proof.

Keywords

Cite

@article{arxiv.1912.12512,
  title  = {Relative Vertex Asphericity},
  author = {Jens Harlander and Stephan Rosebrock},
  journal= {arXiv preprint arXiv:1912.12512},
  year   = {2021}
}
R2 v1 2026-06-23T12:58:07.894Z