English

Minimal Regular graphs with every edge in a triangle

Combinatorics 2024-08-02 v2

Abstract

Considering regular graphs with every edge in a triangle we prove lower bounds for the number of triangles in such graphs. For r-regular graphs with r <= 5 we exhibit families of graphs with exactly that number of triangles and then classify all such graphs using line graphs and even cycle decompositions. Examples of ways to create such r-regular graphs with r >= 6 are also given. In the 5-regular case, these minimal graphs are proven to be the only regular graphs with every edge in a triangle which cannot have an edge removed and still have every edge in a triangle.

Keywords

Cite

@article{arxiv.2106.05879,
  title  = {Minimal Regular graphs with every edge in a triangle},
  author = {James Preen},
  journal= {arXiv preprint arXiv:2106.05879},
  year   = {2024}
}

Comments

9 pages, 6 figures

R2 v1 2026-06-24T03:04:00.408Z