scholarly journals Spectrum localization of regular matrix polynomials and functions

Author(s):  
A. Mazko
2021 ◽  
Vol 37 ◽  
pp. 640-658
Author(s):  
Eunice Y.S. Chan ◽  
Robert M. Corless ◽  
Leili Rafiee Sevyeri

We define generalized standard triples $\boldsymbol{X}$, $\boldsymbol{Y}$, and $L(z) = z\boldsymbol{C}_{1} - \boldsymbol{C}_{0}$, where $L(z)$ is a linearization of a regular matrix polynomial $\boldsymbol{P}(z) \in \mathbb{C}^{n \times n}[z]$, in order to use the representation $\boldsymbol{X}(z \boldsymbol{C}_{1}~-~\boldsymbol{C}_{0})^{-1}\boldsymbol{Y}~=~\boldsymbol{P}^{-1}(z)$ which holds except when $z$ is an eigenvalue of $\boldsymbol{P}$. This representation can be used in constructing so-called  algebraic linearizations for matrix polynomials of the form $\boldsymbol{H}(z) = z \boldsymbol{A}(z)\boldsymbol{B}(z) + \boldsymbol{C} \in \mathbb{C}^{n \times n}[z]$ from generalized standard triples of $\boldsymbol{A}(z)$ and $\boldsymbol{B}(z)$. This can be done even if $\boldsymbol{A}(z)$ and $\boldsymbol{B}(z)$ are expressed in differing polynomial bases. Our main theorem is that $\boldsymbol{X}$ can be expressed using the coefficients of the expression $1 = \sum_{k=0}^\ell e_k \phi_k(z)$ in terms of the relevant polynomial basis. For convenience, we tabulate generalized standard triples for orthogonal polynomial bases, the monomial basis, and Newton interpolational bases; for the Bernstein basis; for Lagrange interpolational bases; and for Hermite interpolational bases.


2008 ◽  
Vol 57 (6) ◽  
pp. 2793-2814 ◽  
Author(s):  
I. Gohberg ◽  
M. A. Kaashoek ◽  
L. Lerer

1988 ◽  
Vol 11 (6) ◽  
pp. 776-882 ◽  
Author(s):  
I. Gohberg ◽  
M. A. Kaashoek ◽  
P. Lancaster

2009 ◽  
Vol 430 (1) ◽  
pp. 579-586 ◽  
Author(s):  
Fernando De Terán ◽  
Froilán M. Dopico

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