On the classes of $n$-Nadir's and $n^*$-Nadir's operators on Hilbert spaces

Authors

  • A. Smati Ecole Normale Supérieure de Bousaada, 28001 Bousaada, Algeria https://orcid.org/0000-0003-4261-8362
  • M. Guesba University of El Oued, El Oued 39000, Algeria
https://doi.org/10.15330/cmp.17.1.137-145

Keywords:

Hilbert space, bounded operator, $n$-Nadir's operator, $n^*$-Nadir's operator, $2$-Nadir's operator
Published online: 2025-06-03

Abstract

The main aim of this paper is to present some new results for Nadir's operator $N=AB^{*}-BA^{*}$, where $A$ and $B$ are two bounded linear operators. We introduce a generalization of this concept, that is, the $n$-Nadir's and $n^*$-Nadir's operators, where $n$ is a positive integer. We present fundamental properties of these operators, including compactness and normality. Additionally, we establish relationships between these classes, we show that the adjoint of $n$-Nadir's operator is $n^*$-Nadir's operator. Furthermore, if $T$ is an $n$-Nadir's operator, such that $ A $ and $ B $ are two bounded commuting normal operators, then $T$ is an $n^*$-Nadir's operator. Moreover, we study these classes in the special case $n = 2$, with some interesting examples. Other related results are also established.

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How to Cite
(1)
Smati, A.; Guesba, M. On the Classes of $n$-Nadir’s and $n^*$-Nadir’s Operators on Hilbert Spaces. Carpathian Math. Publ. 2025, 17, 137-145.