English

Circulant matrices: norm, powers, and positivity

Functional Analysis 2018-04-25 v2

Abstract

In their recent paper "The spectral norm of a Horadam circulant matrix", Merikoski, Haukkanen, Mattila and Tossavainen study under which conditions the spectral norm of a general real circulant matrix C{\bf C} equals the modulus of its row/column sum. We improve on their sufficient condition until we have a necessary one. Our results connect the above problem to positivity of sufficiently high powers of the matrix CC{\bf C^\top C}. We then generalize the result to complex circulant matrices.

Keywords

Cite

@article{arxiv.1803.09526,
  title  = {Circulant matrices: norm, powers, and positivity},
  author = {Marko Lindner},
  journal= {arXiv preprint arXiv:1803.09526},
  year   = {2018}
}
R2 v1 2026-06-23T01:05:01.922Z