On normal operator logarithms

Let X,Y be normal bounded operators on a Hilbert space such that e X=eY. If the spectra of X and Y are contained in the strip S of the complex plane defined by |I(z)|≤π, we show that |X|=|Y|. If Y is only assumed to be bounded, then |X|Y=Y|X|. We give a formula for X-Y in terms of spectral projectio...

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Autor principal: Chiumiento, Eduardo Hernán
Formato: Articulo
Lenguaje:Inglés
Publicado: 2013
Materias:
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/85121
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id I19-R120-10915-85121
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Matemática
Exponential map
Normal operator
Spectral theorem
spellingShingle Matemática
Exponential map
Normal operator
Spectral theorem
Chiumiento, Eduardo Hernán
On normal operator logarithms
topic_facet Matemática
Exponential map
Normal operator
Spectral theorem
description Let X,Y be normal bounded operators on a Hilbert space such that e X=eY. If the spectra of X and Y are contained in the strip S of the complex plane defined by |I(z)|≤π, we show that |X|=|Y|. If Y is only assumed to be bounded, then |X|Y=Y|X|. We give a formula for X-Y in terms of spectral projections of X and Y provided that X,Y are normal and e X=eY. If X is an unbounded self-adjoint operator, which does not have (2k+1)π,k∈ℤ, as eigenvalues, and Y is normal with spectrum in S satisfying eiX=eY, then Y∈{ e iX}″. We give alternative proofs and generalizations of results on normal operator exponentials proved by Schmoeger.
format Articulo
Articulo
author Chiumiento, Eduardo Hernán
author_facet Chiumiento, Eduardo Hernán
author_sort Chiumiento, Eduardo Hernán
title On normal operator logarithms
title_short On normal operator logarithms
title_full On normal operator logarithms
title_fullStr On normal operator logarithms
title_full_unstemmed On normal operator logarithms
title_sort on normal operator logarithms
publishDate 2013
url http://sedici.unlp.edu.ar/handle/10915/85121
work_keys_str_mv AT chiumientoeduardohernan onnormaloperatorlogarithms
bdutipo_str Repositorios
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