English

2.5-Connectivity: Unique Components, Critical Graphs, and Applications

Combinatorics 2020-07-15 v2

Abstract

If a biconnected graph stays connected after the removal of an arbitrary vertex and an arbitrary edge, then it is called 2.5-connected. We prove that every biconnected graph has a canonical decomposition into 2.5-connected components. These components are arranged in a tree-structure. We also discuss the connection between 2.5-connected components and triconnected components and use this to present a linear-time algorithm which computes the 2.5-connected components of a graph. We show that every critical 2.5-connected graph other than K4 can be obtained from critical 2.5-connected graphs of smaller order using simple graph operations. Furthermore, we demonstrate applications of 2.5-connected components in the context of cycle decompositions and cycle packings.

Keywords

Cite

@article{arxiv.2003.01498,
  title  = {2.5-Connectivity: Unique Components, Critical Graphs, and Applications},
  author = {Irene Heinrich and Till Heller and Eva Schmidt and Manuel Streicher},
  journal= {arXiv preprint arXiv:2003.01498},
  year   = {2020}
}

Comments

18 pages, 2 figures

R2 v1 2026-06-23T14:01:58.730Z