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Mathematics
Article . 2026 . Peer-reviewed
License: CC BY
Data sources: Crossref
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New Approach to Generalized Berezin Norms and Rigorous Operator Bounds

Authors: Ghadah Albeladi; Kais Feki; Hala H. Taha;

New Approach to Generalized Berezin Norms and Rigorous Operator Bounds

Abstract

Let HΘ,⟨·,·⟩ be a reproducing kernel Hilbert space over a non-empty set Θ, and let A be a non-zero positive operator on HΘ. This operator induces a semi-inner product given by ⟨ξ,η⟩A=⟨Aξ,η⟩ for all ξ,η∈HΘ, with the associated seminorm ∥ξ∥A=⟨ξ,ξ⟩A. The A-normalized Berezin number and the A-normalized Berezin norm of an A-bounded linear operator C on HΘ are defined by bA(C)=supγ∈ΘA|⟨Cx^γA,x^γA⟩A| and ∥C∥bA=supγ,δ∈ΘA|⟨Cx^γA,x^δA⟩A|, where x^γA=xγ∥xγ∥A and ΘA={γ∈Θ:∥xγ∥A≠0}. The primary aim of this paper is to establish new sharp bounds and inequalities involving these two quantities and related operator-theoretic notions. In doing so, we propose a novel method to address the challenges of operator bounds. Furthermore, we revisit recent results on generalized Berezin norms, in particular those of Huban’s work in 2022. We show that some of these results rely on the incorrect assumption that the A-Berezin number coincides with the A-Berezin norm for A-selfadjoint operators. By providing corrected arguments and employing tools such as the A-Cartesian decomposition and the generalized Buzano inequality, we develop a consistent and rigorous framework for the study of generalized Berezin symbols in semi-Hilbertian spaces.

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
0
Average
Average
Average
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