Essential norms of weighted differentiation composition operators between Zygmund type spaces and Bloch type spaces

Filomat ◽  
2017 ◽  
Vol 31 (9) ◽  
pp. 2877-2889 ◽  
Author(s):  
Amir Sanatpour ◽  
Mostafa Hassanlou
Keyword(s):  
Composition Operators ◽  
Sufficient Conditions ◽  
Essential Norm ◽  
Necessary And Sufficient Conditions ◽  
Norm Estimates ◽  
Type Spaces ◽  
Necessary And Sufficient

We study boundedness of weighted differentiation composition operators Dk?,u between Zygmund type spaces Z? and Bloch type spaces ?. We also give essential norm estimates of such operators in different cases of k ? N and 0 < ?,? < ?. Applying our essential norm estimates, we get necessary and sufficient conditions for the compactness of these operators.

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 Certainμ-Bloch Spaces toQPSpaces

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Chunyu Tan ◽  
Maofa Wang
Keyword(s):  
Composition Operators ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Bloch Spaces ◽  
Type Spaces ◽  
Necessary And Sufficient

Some necessary and sufficient conditions are established for composition operatorsCφto be bounded or compact fromμ-Bloch type spacesBμtoQpspaces. Moreover, the boundedness, compactness, and Fredholmness of composition operators on little spacesQp,0are also characterized.

Weighted composition operators between Fock spaces ℱ∞(ℂ) and ℱp(ℂ)

2019 ◽  
Vol 30 (03) ◽  
pp. 1950015 ◽  
Author(s):  
Le Hai Khoi ◽  
Le Thi Hong Thom ◽  
Pham Trong Tien
Keyword(s):  
Composition Operators ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Connected Components ◽  
Weighted Composition Operators ◽  
Fock Spaces ◽  
Weighted Composition ◽  
Necessary And Sufficient ◽  
Path Connected

In this paper, we establish necessary and sufficient conditions for boundedness and compactness of weighted composition operators acting between Fock spaces [Formula: see text] and [Formula: see text]. We also give complete descriptions of path connected components for the space of composition operators and the space of nonzero weighted composition operators in this context.

scholarly journals New additive results for Cauchy dual and MP-inverse of weighted composition operators

Filomat ◽  
2021 ◽  
Vol 35 (7) ◽  
pp. 2215-2230
Author(s):  
Morteza Sohrabi
Keyword(s):  
Composition Operators ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Weighted Composition Operators ◽  
Weighted Composition ◽  
Necessary And Sufficient

In this paper, we prove some basic results for Cauchy dual of weighted composition operators. Also we introduce some new classes of operators, called ?-hyponormal, ?-quasi-hyponormal, and we provide necessary and sufficient conditions for Cauchy dual and MP-inverse of weighted composition operators on L2(?) to belong to these classes. In addition, we study the complex symmetry of these types of operators. Moreover, some examples are provided to illustrate the obtained results.

scholarly journals Weighted composition operators from Bloch-type into Bers-type spaces

2021 ◽  
Vol 29 (2) ◽  
pp. 243-250
Author(s):  
HAMID VAEZI ◽  
MOHAMAD NAGHLISAR
Keyword(s):  
Composition Operator ◽  
Composition Operators ◽  
Weighted Composition Operator ◽  
Sufficient Conditions ◽  
Weighted Composition Operators ◽  
Type Space ◽  
Bloch Type Space ◽  
Type Spaces ◽  
Weighted Composition ◽  
Necessary And Sufficient

In this paper we consider the weighted composition operator uC_{\varphi} from Bloch-type space B^{\alpha} into Bers-type space H_{\beta}^{\infty}, in three cases, \alpha>1, \alpha=1 and \alpha<1. We give the necessary and sufficient conditions for boundedness and compactness of the above operator.

scholarly journals Basic properties of finite sum of weighted composition operators

Filomat ◽  
2018 ◽  
Vol 32 (11) ◽  
pp. 4005-4019
Author(s):  
Abolghasem Alishahi ◽  
Saeedeh Shamsigamchi ◽  
Ali Ebadian
Keyword(s):  
Composition Operators ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Weighted Composition Operators ◽  
Lp Spaces ◽  
Basic Properties ◽  
Weighted Composition ◽  
Finite Sums ◽  
Finite Sum ◽  
Necessary And Sufficient

In this paper,we continue the study of finite sum of weighted composition operators between different Lp-spaces that was investigated by Jabbarzadeh and Estaremi in 2012. Indeed, we first obtain some necessary and sufficient conditions for boundedness of the finite sums of weighted composition operators between distinct Lp-spaces. In the sequel, we investigate the compactness of finite sum of weighted composition operators. By using theorems of boundedness and compactness, we estimate the essential norms of these operators. Finally, some examples to illustrate the main results are given.

scholarly journals Normal and quasinormal weighted composition operators

1991 ◽  
Vol 33 (3) ◽  
pp. 275-279 ◽  
Author(s):  
James T. Campbell ◽  
Mary Embry-Wardrop ◽  
Richard J. Fleming ◽  
S. K. Narayan
Keyword(s):  
Composition Operator ◽  
Composition Operators ◽  
Weighted Composition Operator ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
The Other ◽  
Weighted Composition Operators ◽  
Weighted Composition ◽  
Necessary And Sufficient

In their paper [1], Campbell and Jamison attempted to give necessary and sufficient conditions for a weighted composition operator on an L2 space to be normal, and to be quasinormal. Those conditions, specifically Theorems I and II of that paper, are not valid (see [2] for precise comments on the other results in that paper). In this paper we present a counterexample to those theorems and state and prove characterizations of quasinormality (Theorem 1 below) and normality (Theorem 2 and Corollary 3 below). We also discuss additional examples and information concerning normal weighted composition operators which contribute to the further understanding of this class.

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