Results 11 to 20 of about 36 (35)
Functions of self‐adjoint operators in ideals of compact operators
Journal of the London Mathematical Society, Volume 95, Issue 1, Page 157-176, February 2017., 2017 Abstract For self‐adjoint operators A,B, a bounded operator J, and a function f:R→C, we obtain bounds in quasi‐normed ideals of compact operators for the difference f(A)J−Jf(B) in terms of the operator AJ−JB. The focus is on functions f that are smooth everywhere except for finitely many points. A typical example is the function f(t)=|t|γ with γ∈(0,1).
Alexander V. Sobolev
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Lipschitz estimates for the Berezin transform
Journal of Function Spaces, Volume 8, Issue 2, Page 103-128, 2010., 2010 We consider the generalized Fock space A2(μm), where μm is the measure with weight e−|z|m, m > 0, with respect to the Lebesgue measure on Cn. Improving upon a recent result of L. Coburn and J. Xia, we show that for any bounded operator X on A2(μm) , the Berezin transform of X satisfies Lipschitz estimates.
Hélène Bommier-Hato, Miroslav Engliš
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Volterra composition operators from generalized weighted weighted Bergman spaces to µ‐Bloch spaces
Journal of Function Spaces, Volume 7, Issue 3, Page 225-240, 2009., 2009 Let φ be a holomorphic self‐map and g be a fixed holomorphic function on the unit ball B. The boundedness and compactness of the operator Tg,φf(z)=∫01f(φ(tz))ℜg(tz)dtt from the generalized weighted Bergman space into the µ‐Bloch space are studied in this paper.
Xiangling Zhu
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A new class of linear operators on ℓ2 and Schur multipliers for them
Journal of Function Spaces, Volume 5, Issue 2, Page 151-165, 2007., 2007 We introduce the space Bw(ℓ2) of linear (unbounded) operators on ℓ2 which map decreasing sequences from ℓ2 into sequences from ℓ2 and we find some classes of operators belonging either to Bw(ℓ2) or to the space of all Schur multipliers on Bw(ℓ2). For instance we show that the space B(ℓ2) of all bounded operators on ℓ2 is contained in the space of all ...
Anca-Nicoleta Marcoci +2 more
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Weighted integral Hankel operators with continuous spectrum
Concrete Operators, 2017 Using the Kato-Rosenblum theorem, we describe the absolutely continuous spectrum of a class of weighted integral Hankel operators in L2(ℝ+). These self-adjoint operators generalise the explicitly diagonalisable operator with the integral kernel sαtα(s ...
Fedele Emilio, Pushnitski Alexander
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Matriceal Lebesgue spaces and Hölder inequality
Journal of Function Spaces, Volume 3, Issue 3, Page 239-249, 2005., 2005 We introduce a class of spaces of infinite matrices similar to the class of Lebesgue spaces Lp(T), 1 ≤ p ≤ ∞, and we prove matriceal versions of Hölder inequality.
Sorina Barza +3 more
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Essential norm of weighted composition operator between α‐Bloch space and β‐Bloch space in polydiscs
International Journal of Mathematics and Mathematical Sciences, Volume 2004, Issue 71, Page 3941-3950, 2004., 2004 Let φ(z) = (φ1(z), …, φn(z)) be a holomorphic self‐map of 𝔻n and ψ(z) a holomorphic function on 𝔻n, where 𝔻n is the unit polydiscs of ℂn. Let 0 < α, β < 1, we compute the essential norm of a weighted composition operator ψCφ between α‐Bloch space ℬα(𝔻n) and β‐Bloch space ℬβ(𝔻n).
Li Songxiao, Zhu Xiangling
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Block Toeplitz operators with frequency‐modulated semi‐almost periodic symbols
International Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 34, Page 2157-2176, 2003., 2003 This paper is concerned with the influence of frequency modulation on the semi‐Fredholm properties of Toeplitz operators with oscillating matrix symbols. The main results give conditions on an orientation‐preserving homeomorphism α of the real line that ensure the following: if b belongs to a certain class of oscillating matrix functions (periodic ...
A. Böttcher, S. Grudsky, I. Spitkovsky
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Toeplitz operators and Wiener-Hopf factorisation: an introduction
Concrete Operators, 2017 Wiener-Hopf factorisation plays an important role in the theory of Toeplitz operators. We consider here Toeplitz operators in the Hardy spaces Hp of the upper half-plane and we review how their Fredholm properties can be studied in terms of a Wiener-Hopf
Câmara M. Cristina
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Toeplitz operators with BMO symbols and the Berezin transform
International Journal of Mathematics and Mathematical Sciences, Volume 2003, Issue 46, Page 2929-2945, 2003., 2003 We prove that the boundedness and compactness of the Toeplitz operator on the Bergman space with a BMO1 symbol is completely determined by the boundary behaviour of its Berezin transform. This result extends the known results in the cases when the symbol is either a positive L1‐function or an L∞ function.
Nina Zorboska
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