scholarly journals A New Essential Norm Estimate of Composition Operators from Weighted Bloch Space into -Bloch Spaces

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
René E. Castillo ◽  
Julio C. Ramos-Fernández ◽  
Edixon M. Rojas
Keyword(s):  
Weight Function ◽  
Unit Disk ◽  
Composition Operator ◽  
Special Function ◽  
Composition Operators ◽  
Bloch Space ◽  
Essential Norm ◽  
Bloch Spaces ◽  
Norm Estimate ◽  
Operator Mapping

Let be any weight function defined on the unit disk and let be an analytic self-map of . In the present paper, we show that the essential norm of composition operator mapping from the weighted Bloch space to -Bloch space is comparable to where for ,   is a certain special function in the weighted Bloch space. As a consequence of our estimate, we extend the results about the compactness of composition operators due to Tjani (2003).

A NEW ESSENTIAL NORM ESTIMATE OF COMPOSITION OPERATORS FROM α-BLOCH SPACES INTO μ-BLOCH SPACES

2013 ◽  
Vol 24 (14) ◽  
pp. 1350104 ◽  
Author(s):  
JULIO C. RAMOS-FERNÁNDEZ
Keyword(s):  
Weight Function ◽  
Unit Disk ◽  
Composition Operator ◽  
Besov Spaces ◽  
Special Function ◽  
Composition Operators ◽  
Bloch Space ◽  
Essential Norm ◽  
Bloch Spaces ◽  
Norm Estimate

Let μ be any weight function defined on the unit disk 𝔻 and let ϕ be an analytic self-map of 𝔻. In this paper, we show that the essential norm of composition operator Cϕ mapping from the α-Bloch space, with α > 0, to μ-Bloch space [Formula: see text] is comparable to [Formula: see text] where, for a ∈ 𝔻, σa is a certain special function in α-Bloch space. As a consequence of our estimate, we extend recent results, about the compactness of composition operators, due to Tjani in [Compact composition operators on Besov spaces, Trans. Amer. Math. Soc.355(11) (2003) 4683–4698] and Malavé Ramírez and Ramos-Fernández in [On a criterion for continuity and compactness of composition operators acting on α-Bloch spaces, C. R. Math. Acad. Sci. Paris351 (2013) 23–26, http://dx.doi.org/10.1016/j.crma.2012.11.013 ].

scholarly journals Norm and Essential Norm of Composition Followed by Differentiation from Logarithmic Bloch Spaces toHμ∞

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Shanli Ye
Keyword(s):  
Lower Bound ◽  
Unit Disk ◽  
Weighted Space ◽  
Bloch Space ◽  
Essential Norm ◽  
Bloch Spaces

In this note we express the norm of composition followed by differentiationDCφfrom the logarithmic Bloch and the little logarithmic Bloch spaces to the weighted spaceHμ∞on the unit disk and give an upper and a lower bound for the essential norm of this operator from the logarithmic Bloch space toHμ∞.

scholarly journals Composition operators on some Möbius invariant Banach spaces

2000 ◽  
Vol 62 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Shamil Makhmutov ◽  
Maria Tjani
Keyword(s):  
Banach Space ◽  
Banach Spaces ◽  
Unit Disk ◽  
Composition Operator ◽  
Composition Operators ◽  
Bloch Space ◽  
Holomorphic Functions ◽  
Mean Oscillation

We characterise the compact composition operators from any Mobius invariant Banach space to VMOA, the space of holomorphic functions on the unit disk U that have vanishing mean oscillation. We use this to obtain a characterisation of the compact composition operators from the Bloch space to VMOA. Finally, we study some properties of hyperbolic VMOA functions. We show that a function is hyperbolic VMOA if and only if it is the symbol of a compact composition operator from the Bloch space to VMOA.

Weighted fractional composition operators on certain function spaces

2019 ◽  
Vol 13 (04) ◽  
pp. 2050082
Author(s):  
D. Borgohain ◽  
S. Naik
Keyword(s):  
Composition Operator ◽  
Fractional Composition ◽  
Composition Operators ◽  
Sufficient Conditions ◽  
Essential Norm ◽  
Function Spaces ◽  
Bloch Spaces ◽  
Type Spaces ◽  
Necessary And Sufficient ◽  
Weighted Type

In this paper, we give some characterizations for the boundedness of weighted fractional composition operator [Formula: see text] from [Formula: see text]-Bloch spaces into weighted type spaces by deriving the bounds of its norm. Also, estimates for essential norm are obtained which gives necessary and sufficient conditions for the compactness of the operator [Formula: see text].

scholarly journals Composition operators from the Bloch space into the spacesQT

2003 ◽  
Vol 2003 (31) ◽  
pp. 1973-1979 ◽  
Author(s):  
Pengcheng Wu ◽  
Hasi Wulan
Keyword(s):  
Unit Disk ◽  
Composition Operator ◽  
Composition Operators ◽  
Bloch Space ◽  
Nondecreasing Function

Suppose thatφ(z)is an analytic self-map of the unit diskΔ. We consider the boundedness of the composition operatorCφfrom Bloch spaceℬinto the spacesQT(QT,0) defined by a nonnegative, nondecreasing functionT(r)on0≤r<∞.

SPECTRA OF LINEAR FRACTIONAL COMPOSITION OPERATORS ON THE GROWTH SPACE AND BLOCH SPACE OF THE UPPER HALF-PLANE

2018 ◽  
Vol 107 (02) ◽  
pp. 199-214
Author(s):  
SHI-AN HAN ◽  
ZE-HUA ZHOU
Keyword(s):  
Spectral Radius ◽  
Half Plane ◽  
Composition Operator ◽  
Fractional Composition ◽  
Composition Operators ◽  
Bloch Space ◽  
Essential Norm ◽  
Essential Spectral Radius ◽  
Growth Space ◽  
Upper Half Plane

In this article, we provide a complete description of the spectra of linear fractional composition operators acting on the growth space and Bloch space over the upper half-plane. In addition, we also prove that the norm, essential norm, spectral radius and essential spectral radius of a composition operator acting on the growth space are all equal.

scholarly journals Composition Operators from p-Bloch Space to q-Bloch Space on the Fourth Cartan-Hartogs Domains

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
Jianbing Su ◽  
Chao Zhang
Keyword(s):  
Composition Operator ◽  
Composition Operators ◽  
Bloch Space ◽  
Bloch Spaces ◽  
Hartogs Domain ◽  
Hartogs Domains

We obtain new generalized Hua’s inequality corresponding to YIV(N,n;K), where YIV(N,n;K) denotes the fourth Cartan-Hartogs domain in CN+n. Furthermore, we introduce the weighted Bloch spaces on YIV(N,n;K) and apply our inequality to study the boundedness and compactness of composition operator Cϕ from βp(YIV(N,n;K)) to βq(YIV(N,n;K)) for p≥0 and q≥0.

Boundedness from Below of Composition Operators on α-Bloch Spaces

2008 ◽  
Vol 51 (2) ◽  
pp. 195-204 ◽  
Author(s):  
Huaihui Chen ◽  
Paul Gauthier
Keyword(s):  
Composition Operator ◽  
Composition Operators ◽  
Bloch Space ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Bloch Spaces ◽  
Necessary And Sufficient ◽  
Bounded Below

AbstractWe give a necessary and sufficient condition for a composition operator on an α-Bloch space with α ≥ 1 to be bounded below. This extends a known result for the Bloch space due to P. Ghatage, J. Yan, D. Zheng, and H. Chen.

scholarly journals Composition operators on Qp spaces

2001 ◽  
Vol 70 (2) ◽  
pp. 161-188 ◽  
Author(s):  
Zengjian Lou
Keyword(s):  
Analytic Function ◽  
Unit Disk ◽  
Function Space ◽  
Composition Operators ◽  
Bloch Space ◽  
Dirichlet Space ◽  
Holomorphic Functions ◽  
Bloch Spaces ◽  
Holomorphic Map ◽  
Analytic Function Space

AbstractA holomorphic map ψ of the unit disk ito itself induces an operator Cψ on holomorphic functions by composition. We characterize bounded and compact composition operators Cψ on Qp spaces, which coincide with the BMOA for p = 1 and Bloch spaces for p > 1. We also give boundedness and compactness characterizations of Cψ from analytic function space X to Qp spaces, X = Dirichlet space D, Bloch space B or B0 = {f: f′ ∈ H∞}.

scholarly journals THE ESSENTIAL NORM OF A WEIGHTED COMPOSITION OPERATOR FROM THE BLOCH SPACE TO H∞

2009 ◽  
Vol 79 (3) ◽  
pp. 487-497 ◽  
Author(s):  
TAKUYA HOSOKAWA
Keyword(s):  
Weight Function ◽  
Composition Operator ◽  
Upper Bound ◽  
Bloch Space ◽  
Weighted Composition Operator ◽  
Essential Norm ◽  
Operator Norm ◽  
Hyperbolic Distance ◽  
Weighted Composition ◽  
Asymptotic Upper Bound

AbstractWe express the operator norm of a weighted composition operator which acts from the Bloch space ℬ to H∞ as the supremum of a quantity involving the weight function, the inducing self-map, and the hyperbolic distance. We also express the essential norm of a weighted composition operator from ℬ to H∞ as the asymptotic upper bound of the same quantity. Moreover we study the estimate of the essential norm of a weighted composition operator from H∞ to itself.

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