English

Tales of Hoffman

Combinatorics 2007-05-23 v2

Abstract

Hofmman's bound on the chromatic number of a graph states that χ1λ1λn\chi \geq 1 - \frac {\lambda_1} {\lambda_n}. Here we show that the same bound, or slight modifications of it, hold for several graph parameters related to the chromatic number: the vector coloring number, the ψ\psi-covering number and the λ\lambda-clustering number.

Keywords

Cite

@article{arxiv.math/0407107,
  title  = {Tales of Hoffman},
  author = {Yonatan Bilu},
  journal= {arXiv preprint arXiv:math/0407107},
  year   = {2007}
}

Comments

short note - 6 pages

R2 v1 2026-07-22T17:07:33.130Z