Para-Hermitian rational matrices

Fuente: arXiv
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Autores principales: Dopico, Froilán, Noferini, Vanni, Quintana, María C., Van Dooren, Paul
Formato: Preprint
Publicado: 2024
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author Dopico, Froilán
Noferini, Vanni
Quintana, María C.
Van Dooren, Paul
author_facet Dopico, Froilán
Noferini, Vanni
Quintana, María C.
Van Dooren, Paul
contents In this paper we study para-Hermitian rational matrices and the associated structured rational eigenvalue problem (REP). Para-Hermitian rational matrices are square rational matrices that are Hermitian for all $z$ on the unit circle that are not poles. REPs are often solved via linearization, that is, using matrix pencils associated to the corresponding rational matrix that preserve the spectral structure. Yet, non-constant polynomial matrices cannot be para-Hermitian. Therefore, given a para-Hermitian rational matrix $R(z)$, we instead construct a $*$-palindromic linearization for $(1+z)R(z)$, whose eigenvalues that are not on the unit circle preserve the symmetries of the zeros and poles of $R(z)$. This task is achieved via Möbius transformations. We also give a constructive method that is based on an additive decomposition into the stable and anti-stable parts of $R(z)$. Analogous results are presented for para-skew-Hermitian rational matrices, i.e., rational matrices that are skew-Hermitian upon evaluation on those points of the unit circle that are not poles.
format Preprint
id arxiv_https___arxiv_org_abs_2407_13563
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Para-Hermitian rational matrices
Dopico, Froilán
Noferini, Vanni
Quintana, María C.
Van Dooren, Paul
Numerical Analysis
65F15, 15A18, 15A22, 15A54, 93B18, 93B20, 93B60
In this paper we study para-Hermitian rational matrices and the associated structured rational eigenvalue problem (REP). Para-Hermitian rational matrices are square rational matrices that are Hermitian for all $z$ on the unit circle that are not poles. REPs are often solved via linearization, that is, using matrix pencils associated to the corresponding rational matrix that preserve the spectral structure. Yet, non-constant polynomial matrices cannot be para-Hermitian. Therefore, given a para-Hermitian rational matrix $R(z)$, we instead construct a $*$-palindromic linearization for $(1+z)R(z)$, whose eigenvalues that are not on the unit circle preserve the symmetries of the zeros and poles of $R(z)$. This task is achieved via Möbius transformations. We also give a constructive method that is based on an additive decomposition into the stable and anti-stable parts of $R(z)$. Analogous results are presented for para-skew-Hermitian rational matrices, i.e., rational matrices that are skew-Hermitian upon evaluation on those points of the unit circle that are not poles.
title Para-Hermitian rational matrices
topic Numerical Analysis
65F15, 15A18, 15A22, 15A54, 93B18, 93B20, 93B60
url https://arxiv.org/abs/2407.13563