English

A new bound for Vizing's conjecture

Combinatorics 2025-09-08 v2

Abstract

For any graph GG, we define the power π(G)\pi(G) as the minimum of the largest number of neighbors in a γ\gamma-set of GG, of any vertex, taken over all γ\gamma-sets of GG. We show that γ(GH)π(G)2π(G)1γ(G)γ(H)\gamma(G\square H)\geq \frac{\pi(G)}{2\pi(G) -1}\gamma(G)\gamma(H). Our methods allow us to prove the following statements for any graphs GG and HH, (1) γ(GH)γ(G)22γ(G)21γ(G)γ(H)\gamma(G\square H)\geq \frac{\lceil \frac{\gamma (G)}{2}\rceil}{2\lceil \frac{\gamma (G)}{2}\rceil-1}\gamma(G)\gamma(H) for odd γ(G)\gamma(G), (2) γ(GH)γ(G)2γ(G)2γ(G)γ(H)\gamma(G\square H)\geq \frac{\gamma (G)}{2\gamma (G)-2}\gamma(G)\gamma(H), for even γ(G)\gamma(G), and (3) a short proof of Vizing's conjecture where γ(G)=3\gamma(G)=3. Our argument relies on establishing efficient correspondences between dominating vertices and subsets of their neighborhoods and then showing a sufficient number of dominating vertices that horizontally dominate vertically undominated cells.

Keywords

Cite

@article{arxiv.1608.02107,
  title  = {A new bound for Vizing's conjecture},
  author = {Elliot Krop and Kimber Wolff},
  journal= {arXiv preprint arXiv:1608.02107},
  year   = {2025}
}

Comments

14 pages

R2 v1 2026-06-22T15:13:55.246Z