Symmetric Representation of Ternary Forms Associated to Some Toeplitz Matrices †

Let A be an n × n complex matrix. Assume the determinantal curve V A...

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Bibliographic Details
Main Authors: Mao-Ting Chien, Hiroshi Nakazato
Format: Article
Language:English
Published: MDPI AG 2018-02-01
Series:Symmetry
Subjects:
Online Access:http://www.mdpi.com/2073-8994/10/3/55
Description
Summary:Let A be an n × n complex matrix. Assume the determinantal curve V A = { [ ( x , y , z ) ] ∈ CP 2 : F A ( x , y , z ) = det ( x ℜ ( A ) + y ℑ ( A ) + z I n ) = 0 } is a rational curve. The Fiedler formula provides a complex symmetric matrix S satisfying F S ( x , y , z ) = F A ( x , y , z ) . It is also known that every Toeplitz matrix is unitarily similar to a symmetric matrix. In this paper, we investigate the unitary similarity of the symmetric matrix S and the matrix A in the Fiedler theorem for a specific parametrized family of 4 × 4 nilpotent Toeplitz matrices A. We show that there are either one or at least three unitarily inequivalent symmetric matrices which admit the determinantal representation of the ternary from F A ( x , y , z ) associated to the specific 4 × 4 nilpotent Toeplitz matrices.
ISSN:2073-8994