English

Graphs and Hermitian matrices: discrepancy and singular values

Combinatorics 2007-05-23 v2 Commutative Algebra

Abstract

We introduce a measure of discrepancy of Hermitian matrices and establish an inequality between the second singular value of a Hermitian matrix and its discrepancy. These results are applied to answer two questions of Fan Chung about graph eigenvalues.

Keywords

Cite

@article{arxiv.math/0404559,
  title  = {Graphs and Hermitian matrices: discrepancy and singular values},
  author = {Bela Bollobas and Vladimir Nikiforov},
  journal= {arXiv preprint arXiv:math/0404559},
  year   = {2007}
}

Comments

22 pages, accepted in Discrete Math. Rev 2 - some typos corrected, thanks Herbert Wilf