Lower Bound on the Chromatic Number by Spectra of Weighted Adjacency Matrices
Paweł Wocjan, Dominik Janzing, Thomas Beth · arXiv (Cornell University) · 2001
A lower bound on the chromatic number of a graph is derived by majorization of spectra of weighted adjacency matrices. These matrices are given by Hadamard products of the adjacency matrix and arbitrary Hermitian matrices.