Abstract
In this paper, we mainly deal with sequences of bounded linear operators on Hilbert space. The main result is the so-called squeeze theorem (or sandwich rule) for convergent sequences of self-adjoint operators. We show that this theorem remains valid for all three main topologies on B(H). Some interesting consequences are given.
Similar content being viewed by others
References
I. Boucif, S. Dehimi and M. H. Mortad, On the absolute value of unbounded operators, J. Operator Theory, 82 (2019), 285–306.
Ch. Chellai and M. H. Mortad, The sandwich rule for sequences of self-adjoint operators and some applications, arXiv:2104.07093v2 (2021).
S. Dehimi and M. H. Mortad, Generalizations of Reid inequality, Math. Slovaca, 68 (2018), 1439–1446.
P. R. Halmos, A Hilbert Space Problem Book, 2nd ed., Springer (1982).
C. S. Kubrusly, Hilbert Space Operators. A Problem Solving Approach, Birkhäuser Boston, Inc. (Boston, MA, 2003).
C. S. Kubrusly, The Elements of Operator Theory, 2nd ed., Birkhäuser/Springer (New York, 2011).
M. H. Mortad, An Operator Theory Problem Book, World Scientific Publishing Co. (2018).
M. H. Mortad, On the absolute value of the product and the sum of linear operators, Rend. Circ. Mat. Palermo, II. Ser., 68 (2019), 247–257.
M. H. Mortad, Counterexamples in Operator Theory, Birkhäuser/Springer (Cham, 2022).
J. Weidmann, Linear Operators in Hilbert Spaces, Springer (1980).
Acknowledgement
The authors wish to warmly thank the referee for shortening the proof of Theorem 2.2 (cf. [2]), and for extending the conclusion of Corollary 2.6 to the case of the strong operator topology.
Author information
Authors and Affiliations
Corresponding author
Additional information
M. H. Mortad is partially supported by “Laboratoire d’Analyse Mathématique et Applications”.
Rights and permissions
About this article
Cite this article
Chellali, C., Mortad, M.H. The Sandwich Rule for Sequences of Self-Adjoint Operators and Some Applications. Anal Math 48, 991–996 (2022). https://doi.org/10.1007/s10476-022-0171-5
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10476-022-0171-5