Open Access

# Subscalarity of $k$-quasi-class $A$ operators

### Abstract

In this paper, we show that every $k$-quasi-class $A$ operator has a scalar extension and give some spectral properties of the scalar extensions of $k$-quasi-class $A$ operators. As a corollary, we get that such an operator with rich spectrum has a nontrivial invariant subspace.

Key words: Class $A$ operator, $k$-quasi-class $A$ operators, invariant subspace, subscalar.

### Article Information

 Title Subscalarity of $k$-quasi-class $A$ operators Source Methods Funct. Anal. Topology, Vol. 25 (2019), no. 2, 177-188 MathSciNet MR3978681 Milestones Received 08/02/2019; Revised 02/03/2019 Copyright The Author(s) 2019 (CC BY-SA)

### Authors Information

M. H. M. Rashid
Department of Mathematics, Faculty of Science P. O. Box(7), Mu’tah university, AlKarak-Jordan

### Citation Example

M. H. M. Rashid, Subscalarity of $k$-quasi-class $A$ operators, Methods Funct. Anal. Topology 25 (2019), no. 2, 177-188.

### BibTex

@article {MFAT1172,
AUTHOR = {M. H. M. Rashid},
TITLE = {Subscalarity of $k$-quasi-class $A$ operators},
JOURNAL = {Methods Funct. Anal. Topology},
FJOURNAL = {Methods of Functional Analysis and Topology},
VOLUME = {25},
YEAR = {2019},
NUMBER = {2},
PAGES = {177-188},
ISSN = {1029-3531},
MRNUMBER = {MR3978681},
URL = {http://mfat.imath.kiev.ua/article/?id=1172},
}

Coming Soon.