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Tensor product of left polaroid operators

Functional Analysis 2014-01-24 v1

Abstract

A Banach space operator TB(X)T\in B(X) is left polaroid if for each λisoσa(T)\lambda\in\hbox{iso}\sigma_a(T) there is an integer d(λ)d(\lambda) such that asc (Tλ)=d(λ)<(T-\lambda)=d(\lambda)<\infty and (Tλ)d(λ)+1X(T-\lambda)^{d(\lambda)+1}X is closed; TT is finitely left polaroid if asc (Tλ)<(T-\lambda)<\infty, (Tλ)X(T-\lambda)X is closed and dim(Tλ)1(0)<\dim(T-\lambda)^{-1}(0)<\infty at each λiso σa(T)\lambda\in\hbox{iso }\sigma_a(T). The left polaroid property transfers from AA and BB to their tensor product ABA\otimes B, hence also from AA and BB^* to the left-right multiplication operator τAB\tau_{AB}, for Hilbert space operators; an additional condition is required for Banach space operators. The finitely left polaroid property transfers from AA and BB to their tensor product ABA\otimes B if and only if 0∉isoσa(AB)0\not\in\hbox{iso}\sigma_a(A\otimes B); a similar result holds for τAB\tau_{AB} for finitely left polaroid AA and BB^*.

Keywords

Cite

@article{arxiv.1401.5939,
  title  = {Tensor product of left polaroid operators},
  author = {Enrico Boasso and B. P. Duggal},
  journal= {arXiv preprint arXiv:1401.5939},
  year   = {2014}
}

Comments

10 pages, original research article