Oblique projections and abstract splines

Given a closed subspace L of a Hilbert space ℋ and a bounded linear operator A ∈ L(ℋ) which is positive, consider the set of all A-self-adjoint projections onto Y: ℘(A,Y) = {Q ∈ L(ℋ): Q2 = Q, Q(ℋ) = Y, AQ = Q*A}. In addition, if ℋ1 is another Hilbert space, T : ℋ → ℋ1 is a bounded linear operator su...

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Autores principales: Corach, Gustavo, Maestripieri, A., Stojanoff, Demetrio
Formato: Articulo
Lenguaje:Inglés
Publicado: 2002
Materias:
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/84951
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id I19-R120-10915-84951
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Matemática
spellingShingle Matemática
Corach, Gustavo
Maestripieri, A.
Stojanoff, Demetrio
Oblique projections and abstract splines
topic_facet Matemática
description Given a closed subspace L of a Hilbert space ℋ and a bounded linear operator A ∈ L(ℋ) which is positive, consider the set of all A-self-adjoint projections onto Y: ℘(A,Y) = {Q ∈ L(ℋ): Q2 = Q, Q(ℋ) = Y, AQ = Q*A}. In addition, if ℋ1 is another Hilbert space, T : ℋ → ℋ1 is a bounded linear operator such that T*T = A and ξ ∈ ℋ, consider the set of (T, Y) spline interpolants to ξ: sp(T, Y, ξ) = { η ε ξ + Y : ∥Tη∥ = min ∥T(ξ + σ)∥}. A strong relationship exists between ℘(A, Y) and s p(T, Y, ξ). In fact, ∥(A, Y) is not empty if and only if s p(T, Y, ξ) is not empty for every ξ ∈ ℋ. In this case, for any ξ ∈ ℋ\Y it holds s p(T, Y, ξ) = {(1 - Q)ξ:Q ∈ ℘(A, Y)} and for any ξ ∈ ℋ, the unique vector of s p(T, Y, ξ) with minimal norm is (1 - PA,Y)ξ, where PA,L is a distinguished element of ℘(A, Y). These results offer a generalization to arbitrary operators of several theorems by de Boor, Atteia, Sard and others, which hold for closed range operators.
format Articulo
Articulo
author Corach, Gustavo
Maestripieri, A.
Stojanoff, Demetrio
author_facet Corach, Gustavo
Maestripieri, A.
Stojanoff, Demetrio
author_sort Corach, Gustavo
title Oblique projections and abstract splines
title_short Oblique projections and abstract splines
title_full Oblique projections and abstract splines
title_fullStr Oblique projections and abstract splines
title_full_unstemmed Oblique projections and abstract splines
title_sort oblique projections and abstract splines
publishDate 2002
url http://sedici.unlp.edu.ar/handle/10915/84951
work_keys_str_mv AT corachgustavo obliqueprojectionsandabstractsplines
AT maestripieria obliqueprojectionsandabstractsplines
AT stojanoffdemetrio obliqueprojectionsandabstractsplines
bdutipo_str Repositorios
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