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On Closed-Ness and Commutativity Properties of N-Posinormal and M-Hyponormal Class of Operators in Hilbert Spaces


Authors : Philemon Murimi; Sammy Musundi; Dr. Peter Muiruri

Volume/Issue : Volume 11 - 2026, Issue 6 - June


Google Scholar : https://tinyurl.com/tvs3t3u

Scribd : https://tinyurl.com/2j4493ys

DOI : https://doi.org/10.38124/ijisrt/26jun1729

Note : A published paper may take 4-5 working days from the publication date to appear in PlumX Metrics, Semantic Scholar, and ResearchGate.


Abstract : interrupter for the operator T. This paper studied the closed-ness aspect and commutativ-ity properties of this operator and the related class of m-hyponormal operator in Hilbert space. The results showed that if T is n-posinormal operator then,T∗ is also n-posinormal operator.The results also were extended to the class of m-hyponormal operators. Similarly, the results showed that, if T is n-posinormal operator in Hilbert space H, then any operator S, unitary equivalent to T, is also n-posinormal operator. Furthermore, the results showed that the class of nposinormal and m-hyponormal operators is closed in the operator norm topology. To achieve these results, the properties of linear operators, normal operators and posinormal operators were extended to the higher order n-posinormal and mhyponormal operators.

Keywords : Normal Operators, Hyponormal Operators, Adjoints, N Power Normal Opera-Tors, M-Hyponormal Operators and NPosinormal Operators.

References :

  1. Adnan A. S. Jibril, On n-Power Normal Operators, The Arabian Journal for Sciences and Engineering, Vol. 33, No. 2A, 2008, 247 - 251.
  2. Kubrusly C.S (2012), Spectral Theory of Operators on Hilbert Spaces, Birkhauser/Springer, New York.
  3. Rhaly H, JR.(2014), A superclass of the posinormal operators, New York J. Math, 30 , 497–506.
  4. Mahmoud, S. A. O. A., Saddi, A.,Gherairi, K. (2020). Some results on higher orders quasi-isometries. Hacettepe Journal of Mathematics and Statistics, 49(4), 1315-1333.
  5. Lee M.Y and S. H. Lee (2006), On powers of p -posinormal operators, Sci. Math. Jpn. 64 , 97–101.
  6. Ould Beiba, E. M. (2021). n-Power-posinormal operators. Methods of Functional Analysis and Topology, 27(1), 18-24.
  7. Bourdon P.S and D. Thompson (2022), Posinormal composition operators on H2,J. Math. Anal.
  8. S. H. Lee, W. Y. Lee, (1996). A spectral mapping theorem for the Weyl spectrum.,Glasgow Math. J. 38, 61–4.
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interrupter for the operator T. This paper studied the closed-ness aspect and commutativ-ity properties of this operator and the related class of m-hyponormal operator in Hilbert space. The results showed that if T is n-posinormal operator then,T∗ is also n-posinormal operator.The results also were extended to the class of m-hyponormal operators. Similarly, the results showed that, if T is n-posinormal operator in Hilbert space H, then any operator S, unitary equivalent to T, is also n-posinormal operator. Furthermore, the results showed that the class of nposinormal and m-hyponormal operators is closed in the operator norm topology. To achieve these results, the properties of linear operators, normal operators and posinormal operators were extended to the higher order n-posinormal and mhyponormal operators.

Keywords : Normal Operators, Hyponormal Operators, Adjoints, N Power Normal Opera-Tors, M-Hyponormal Operators and NPosinormal Operators.

Paper Submission Last Date
31 - July - 2026

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