English

Quartic graphs with every edge in a triangle

Combinatorics 2013-08-02 v1

Abstract

We characterise the quartic (i.e. 4-regular) multigraphs with the property that every edge lies in a triangle. The main result is that such graphs are either squares of cycles, line multigraphs of cubic multigraphs, or are obtained from these by a number of simple subgraph-replacement operations. A corollary of this is that a simple quartic graph with every edge in a triangle is either the square of a cycle, the line graph of a cubic graph or a graph obtained from the line multigraph of a cubic multigraph by replacing triangles with copies of K_{1,1,3}.

Keywords

Cite

@article{arxiv.1308.0081,
  title  = {Quartic graphs with every edge in a triangle},
  author = {Florian Pfender and Gordon F. Royle},
  journal= {arXiv preprint arXiv:1308.0081},
  year   = {2013}
}
R2 v1 2026-06-22T01:01:57.116Z