English

Representation and normality of Hyponormal operators in the closure of $\mathcal{AN}$-operators

Functional Analysis 2022-08-16 v1 Operator Algebras

Abstract

Let H1H_1, H2H_2 be complex Hilbert spaces. A bounded linear operator T:H1H2T : H_1 \to H_2 is said to be norm attaining if there exists a unit vector xH1x \in H_1 such that Tx=T\|Tx\| = \|T\|. If TM:MH2T|_{M} : M \to H_2 is norm attaining for every closed subspace MM of H1H_1, then we say that TT is an absolutely norm attaining (AN\mathcal{AN}-operator). If the norm of the operator is replaced by the minimum modulus m(T)=inf{Tx:xH1,x=1}m(T) = \inf\{\|Tx\| : x \in H_1, \|x\| =1\}, then TT is said to be a minimum attaining and an absolutely minimum attaining operator (AM\mathcal{AM}-operator), respectively. In this article, we give representations of quasinormal AN\mathcal{AN}, AM\mathcal{AM}-operators and the operators in the closure of these two classes. Later we extend these results to the class of hyponormal operators in the closure of AN\mathcal{AN}-operators and a further look at some sufficient conditions under which these operators become normal.

Keywords

Cite

@article{arxiv.2208.06574,
  title  = {Representation and normality of Hyponormal operators in the closure of $\mathcal{AN}$-operators},
  author = {G. Ramesh and Shanola S. Sequeira},
  journal= {arXiv preprint arXiv:2208.06574},
  year   = {2022}
}

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