Opuscula Mathematica
Opuscula Math. 38, no. 6 (2018), 849-857

Circulant matrices: norm, powers, and positivity

Marko Lindner
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 \({\bf C}\) 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 \({\bf C^\top C}\). We then generalize the result to complex circulant matrices.
Keywords: spectral norm, circulant matrix, eventually positive semigroups.
Mathematics Subject Classification: 15A60, 15B05, 15B48.
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References ▼
  1. [1] P.J. Davis, Circulant Matrices, Wiley, 1979.
  2. [2] J.K. Merikoski, P. Haukkanen, M. Mattila, T. Tossavainen, The spectral norm of a Horadam circulant matrix, JP Journal of Algebra, Number Theory and Applications, to appear.
  3. [3] J.K. Merikoski, P. Haukkanen, M. Mattila, T. Tossavainen, On the spectral and Frobenius norm of a generalized Fibonacci \(r\)-circulant matrix, Special Matrices 6 (2018), 23-36.
About the authors ▼
Marko Lindner
Techn. Univ. Hamburg (TUHH), Institut Mathematik, D-21073 Hamburg, Germany
About the article ▼
Communicated by P.A. Cojuhari.
Received: 2018-03-28.
Revised: 2018-04-04.
Accepted: 2018-04-04.
Published online: 2018-07-05.
Cite this article as ▼
Marko Lindner, Circulant matrices: norm, powers, and positivity, Opuscula Math. 38, no. 6 (2018), 849-857, https://doi.org/10.7494/OpMath.2018.38.6.849.
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