منابع مشابه
Properties and Preservers of the Pseudospectrum
Dedicated to Professor Hans Schneider. Abstract The interplay between the algebraic and analytic properties of a matrix and the geometric properties of its pseudospectrum is investigated. It is shown that one can characterize Hermitian matrices, positive semi-definite matrices, orthogonal projections, unitary matrices, etc. in terms of the pseudospectrum. Also, characterizations are given to ma...
متن کاملOn the Boundary of the Pseudospectrum and Its Fault Points
The study of pseudospectra of linear transformations has become a significant part of numerical linear algebra and related areas. A large body of research activity has focused on how to compute these sets for a given spectral problem with, possibly, certain underlying structure. The theme of this paper was motivated by the question: How effective are path-following procedures for tracing the ps...
متن کاملA Note on Positivity Preservers
In this short follow-up of [3] we answer some questions posed there. In particular, we characterize two natural classes of linear operators acting on R[x1, x2, ..., xn] which (i) preserve the set of positive n-variate polynomials; (ii) either act diagonally in the monomial basis of R[x1, x2, ..., xn] or are translation-invariant.
متن کاملSpectrum through pseudospectrum
This report was written in 2001 and it is a translation of work that was originally published in Greek, in the author’s diploma thesis in July 1998. It may contain minor mistakes and should not be considered a complete study. It however touches upon several of the considerations that will be included in the complete paper. The work was done jointly with E. Gallopoulos and was presented at the F...
متن کاملEigenvalues, Pseudospectrum and Structured Perturbations
We investigate the behavior of eigenvalues under structured perturbations. We show that for many common structures such as (complex) symmetric, Toeplitz, symmetric Toeplitz, circulant and others the structured condition number is equal to the unstructured condition number for normwise perturbations, and prove similar results for real perturbations. An exception are complex skewsymmetric matrice...
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ژورنال
عنوان ژورنال: Proyecciones (Antofagasta)
سال: 2020
ISSN: 0717-6279
DOI: 10.22199/issn.0717-6279-2020-06-0089