scholarly journals Toeplitz operators on weighted spaces of holomorphic functions

2008 ◽  
Vol 103 (1) ◽  
pp. 40 ◽  
Author(s):  
Anahit Harutyunyan ◽  
Wolfgang Lusky
Keyword(s):  
Toeplitz Operator ◽  
Unit Disk ◽  
Essential Spectrum ◽  
Complex Plane ◽  
Toeplitz Operators ◽  
Holomorphic Functions ◽  
Weighted Spaces ◽  
Norm Estimates ◽  
Spaces Of Holomorphic Functions

We define a notion of Toeplitz operator on certain spaces of holomorphic functions on the unit disk and on the complex plane which are endowed with a weighted sup-norm. We establish boundedness and compactness conditions, give norm estimates and characterize the essential spectrum of these operators for many symbols.

Isometries of weighted spaces of holomorphic functions on unbounded domains

2009 ◽  
Vol 139 (2) ◽  
pp. 253-271 ◽  
Author(s):  
Christopher Boyd ◽  
Pilar Rueda
Keyword(s):  
Half Plane ◽  
Complex Plane ◽  
Unbounded Domains ◽  
Holomorphic Functions ◽  
Weighted Spaces ◽  
Bounded Domains ◽  
Spaces Of Holomorphic Functions ◽  
The Right

We study isometries between weighted spaces of holomorphic functions on unbounded domains in ℂn. We show that weighted spaces of holomorphic functions on unbounded domains may exhibit behaviour different from that observed on bounded domains. We calculate the isometries for specific weights on the complex plane and the right half-plane.

Isomorphism classes of weighted spaces of holomorphic functions on some subsets of complex plane

2019 ◽  
Vol 26 (1) ◽  
pp. 13-19
Author(s):  
Mohammad Ali Ardalani
Keyword(s):  
Complex Plane ◽  
Holomorphic Functions ◽  
Growth Conditions ◽  
Weighted Spaces ◽  
Isomorphism Classes ◽  
Spaces Of Holomorphic Functions

Abstract In this paper, we consider the weighted spaces of holomorphic functions on some open subsets of the complex plane and characterize the isomorphism classes of these spaces whenever our weights are warped and satisfy certain growth conditions.

scholarly journals Hyponormal Toeplitz operators on H2(T) with polynomial symbols

1996 ◽  
Vol 144 ◽  
pp. 179-182 ◽  
Author(s):  
Dahai Yu
Keyword(s):  
Functional Equation ◽  
Hardy Space ◽  
Closed Form ◽  
Unit Circle ◽  
Toeplitz Operator ◽  
Explicit Expression ◽  
Complex Plane ◽  
Toeplitz Operators ◽  
Computing Process

Let T be the unit circle on the complex plane, H2(T) be the usual Hardy space on T, Tø be the Toeplitz operator with symbol Cowen showed that if f1 and f2 are functions in H such that is in Lø, then Tf is hyponormal if and only if for some constant c and some function g in H∞ with Using it, T. Nakazi and K. Takahashi showed that the symbol of hyponormal Toeplitz operator Tø satisfies and and they described the ø solving the functional equation above. Both of their conditions are hard to check, T. Nakazi and K. Takahashi remarked that even “the question about polynomials is still open” [2]. Kehe Zhu gave a computing process by way of Schur’s functions so that we can determine any given polynomial ø such that Tø is hyponormal [3]. Since no closed-form for the general Schur’s function is known, it is still valuable to find an explicit expression for the condition of a polynomial á such that Tø is hyponormal and depends only on the coefficients of ø, here we have one, it is elementary and relatively easy to check. We begin with the most general case and the following Lemma is essential.

scholarly journals Multipliers on vector spaces of holomorphic functions

2000 ◽  
Vol 159 ◽  
pp. 167-178 ◽  
Author(s):  
Hermann Render ◽  
Andreas Sauer
Keyword(s):  
Uniqueness Theorem ◽  
Complex Plane ◽  
Hadamard Product ◽  
Holomorphic Functions ◽  
Vector Spaces ◽  
Spaces Of Holomorphic Functions ◽  
Coefficient Multipliers ◽  
Multiplier Algebras

Let G be a domain in the complex plane containing zero and H(G) be the set of all holomorphic functions on G. In this paper the algebra M(H(G)) of all coefficient multipliers with respect to the Hadamard product is studied. Central for the investigation is the domain introduced by Arakelyan which is by definition the union of all sets with w ∈ Gc. The main result is the description of all isomorphisms between these multipliers algebras. As a consequence one obtains: If two multiplier algebras M(H(G1)) and M(H(G2)) are isomorphic then is equal to Two algebras H(G1) and H(G2) are isomorphic with respect to the Hadamard product if and only if G1 is equal to G2. Further the following uniqueness theorem is proved: If G1 is a domain containing 0 and if M(H(G)) is isomorphic to H(G1) then G1 is equal to .

scholarly journals Strict density inequalities for sampling and interpolation in weighted spaces of holomorphic functions

2019 ◽  
Vol 277 (12) ◽  
pp. 108282 ◽  
Author(s):  
Karlheinz Gröchenig ◽  
Antti Haimi ◽  
Joaquim Ortega-Cerdà ◽  
José Luis Romero
Keyword(s):  
Holomorphic Functions ◽  
Weighted Spaces ◽  
Spaces Of Holomorphic Functions

Composition operators on weighted spaces of holomorphic functions on the upper half plane

2018 ◽  
Vol 122 (1) ◽  
pp. 141
Author(s):  
Wolfgang Lusky
Keyword(s):  
Half Plane ◽  
Composition Operator ◽  
Unit Disc ◽  
Composition Operators ◽  
Bounded Operator ◽  
Holomorphic Functions ◽  
Weighted Spaces ◽  
Weight Functions ◽  
Spaces Of Holomorphic Functions ◽  
Upper Half Plane

We consider moderately growing weight functions $v$ on the upper half plane $\mathbb G$ called normal weights which include the examples $(\mathrm{Im} w)^a$, $w \in \mathbb G$, for fixed $a > 0$. In contrast to the comparable, well-studied situation of normal weights on the unit disc here there are always unbounded composition operators $C_{\varphi }$ on the weighted spaces $Hv(\mathbb G)$. We characterize those holomorphic functions $\varphi \colon \mathbb G \rightarrow \mathbb G$ where the composition operator $C_{\varphi } $ is a bounded operator $Hv(\mathbb G) \rightarrow Hv(\mathbb G)$ by a simple property which depends only on $\varphi $ but not on $v$. Moreover we show that there are no compact composition operators $C_{\varphi }$ on $Hv(\mathbb G)$.

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