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Composition-Differentiation Operator On Hardy-Hilbert Space of Dirichlet Series

2025/02/27 by Allu, Vasudevarao, Mondal, Dipon Kumar
#30B50 #30H10 #47B33 #47B38 #Complex Variables (math.CV) #FOS: Mathematics #Functional Analysis (math.FA)

paper · doi:10.48550/arxiv.2502.19939

Abstract

In this paper, we establish a compactness criterion for the composition-differentiation operator \( DΦ\) in terms of a decay condition of the mean counting function at the boundary of a half-plane. We provide a sufficient condition of the boundedness of the operator \( DΦ\) for the symbol \( Φ\) with zero characteristic. Additionally, we investigate an estimate for the norm of \( DΦ\) in the Hardy-Hilbert space of Dirichlet series, specifically with the symbol \( Φ(s) = c1 + c2 2-s \). We also derive an estimate for the approximation numbers of the operator \( DΦ\). Moreover, we determine an explicit conditions under which the operator \( DΦ\) is self-adjoint and normal. Finally, we describe the spectrum of \( DΦ\) when the symbol \( Φ(s) = c1 + c2 2-s \).

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