Index of Hadamard multiplication by positive matrices II

For each n×n positive semidefinite matrix A we define the minimal index I(A)=max{λ≥0:A∘B≥λB for all B≥0} and, for each norm N, the N-index I<SUB>N</SUB>(A)=min{N(A∘B):B≥0 and N(B)=1}, where A ∘ B=[a<SUB>ij</SUB>b<SUB>ij</SUB>] is the Hadamard or Schur product of A...

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Autores principales: Corach, Gustavo, Stojanoff, Demetrio
Formato: Articulo
Lenguaje:Inglés
Publicado: 2001
Materias:
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/84728
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id I19-R120-10915-84728
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Exactas
Matemática
47A30
47B15
Hadamard product
Norm inequalities
Positive semidefinite matrices
spellingShingle Ciencias Exactas
Matemática
47A30
47B15
Hadamard product
Norm inequalities
Positive semidefinite matrices
Corach, Gustavo
Stojanoff, Demetrio
Index of Hadamard multiplication by positive matrices II
topic_facet Ciencias Exactas
Matemática
47A30
47B15
Hadamard product
Norm inequalities
Positive semidefinite matrices
description For each n×n positive semidefinite matrix A we define the minimal index I(A)=max{λ≥0:A∘B≥λB for all B≥0} and, for each norm N, the N-index I<SUB>N</SUB>(A)=min{N(A∘B):B≥0 and N(B)=1}, where A ∘ B=[a<SUB>ij</SUB>b<SUB>ij</SUB>] is the Hadamard or Schur product of A=[a<SUB>ij</SUB>] and B=[b<SUB>ij</SUB>] and B≥0 means that B is a positive semidefinite matrix. A comparison between these indexes is done, for different choices of the norm N. As an application we find, for each bounded invertible selfadjoint operator S on a Hilbert space, the best constant M(S) such that ∥STS+S<SUP>-1</SUP>TS<SUP>-1</SUP>∥≥M(S)∥T∥ for all T≥0.
format Articulo
Articulo
author Corach, Gustavo
Stojanoff, Demetrio
author_facet Corach, Gustavo
Stojanoff, Demetrio
author_sort Corach, Gustavo
title Index of Hadamard multiplication by positive matrices II
title_short Index of Hadamard multiplication by positive matrices II
title_full Index of Hadamard multiplication by positive matrices II
title_fullStr Index of Hadamard multiplication by positive matrices II
title_full_unstemmed Index of Hadamard multiplication by positive matrices II
title_sort index of hadamard multiplication by positive matrices ii
publishDate 2001
url http://sedici.unlp.edu.ar/handle/10915/84728
work_keys_str_mv AT corachgustavo indexofhadamardmultiplicationbypositivematricesii
AT stojanoffdemetrio indexofhadamardmultiplicationbypositivematricesii
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