# Some invariant subspaces for A-contractions and applications

Extracta Mathematicae (2006)

- Volume: 21, Issue: 3, page 221-247
- ISSN: 0213-8743

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topSuciu, Laurian. "Some invariant subspaces for A-contractions and applications." Extracta Mathematicae 21.3 (2006): 221-247. <http://eudml.org/doc/41862>.

@article{Suciu2006,

abstract = {Some invariant subspaces for the operators A and T acting on a Hilbert space H and satisfying T*AT ≤ A and A ≥ 0, are presented. Especially, the largest invariant subspace for A and T on which the equality T* AT = A occurs, is studied in connections to others invariant or reducing subspaces for A, or T. Such subspaces are related to the asymptotic form of the subspace quoted above, this form being obtained using the operator limit of the sequence \{T*nATn; n ≥ 1\}. More complete results are given in the case when AT = A1/2TA1/2. Also, several applications for quasinormal operators are derived, involving their unitary, isometric and quasi-isometric parts, as well as their asymptotic behaviour.},

author = {Suciu, Laurian},

journal = {Extracta Mathematicae},

keywords = {Teoría de operadores; Operadores lineales; Subespacio invariante; Contracción},

language = {eng},

number = {3},

pages = {221-247},

title = {Some invariant subspaces for A-contractions and applications},

url = {http://eudml.org/doc/41862},

volume = {21},

year = {2006},

}

TY - JOUR

AU - Suciu, Laurian

TI - Some invariant subspaces for A-contractions and applications

JO - Extracta Mathematicae

PY - 2006

VL - 21

IS - 3

SP - 221

EP - 247

AB - Some invariant subspaces for the operators A and T acting on a Hilbert space H and satisfying T*AT ≤ A and A ≥ 0, are presented. Especially, the largest invariant subspace for A and T on which the equality T* AT = A occurs, is studied in connections to others invariant or reducing subspaces for A, or T. Such subspaces are related to the asymptotic form of the subspace quoted above, this form being obtained using the operator limit of the sequence {T*nATn; n ≥ 1}. More complete results are given in the case when AT = A1/2TA1/2. Also, several applications for quasinormal operators are derived, involving their unitary, isometric and quasi-isometric parts, as well as their asymptotic behaviour.

LA - eng

KW - Teoría de operadores; Operadores lineales; Subespacio invariante; Contracción

UR - http://eudml.org/doc/41862

ER -