Spectra of composition operators on algebras of analytic functions on Banach spaces

2009 ◽  
Vol 139 (1) ◽  
pp. 107-121 ◽  
Author(s):  
P. Galindo ◽  
T. W. Gamelin ◽  
Mikael Lindström
Keyword(s):  
Banach Space ◽  
Hilbert Space ◽  
Fixed Point ◽  
Unit Ball ◽  
Banach Spaces ◽  
Composition Operator ◽  
Composition Operators ◽  
Open Unit ◽  
Open Unit Ball ◽  
Analytic Symbol

Let E be a Banach space, with unit ball BE. We study the spectrum and the essential spectrum of a composition operator on H∞(BE) determined by an analytic symbol with a fixed point in BE. We relate the spectrum of the composition operator to that of the derivative of the symbol at the fixed point. We extend a theorem of Zheng to the context of analytic symbols on the open unit ball of a Hilbert space.

scholarly journals On approximating curves associated with nonexpansive mappings

2011 ◽  
Vol 27 (1) ◽  
pp. 142-147
Author(s):  
FRANCESCA VETRO ◽  
Keyword(s):  
Banach Space ◽  
Hilbert Space ◽  
Unit Ball ◽  
Nonexpansive Mappings ◽  
Complex Hilbert Space ◽  
Open Unit ◽  
Open Unit Ball ◽  
Holomorphic Map ◽  
Nonexpansive Map ◽  
The Hyperbolic Metric

Let X be a Banach space with metric d. Let T, N : X → X be a strict d-contraction and a d-nonexpansive map, respectively. In this paper we investigate the properties of the approximating curve associated with T and N. Moreover, following [3], we consider the approximating curve associated with a holomorphic map f : B → α B and a ρ-nonexpansive map M : B → B, where B is the open unit ball of a complex Hilbert space H, ρ is the hyperbolic metric defined on B and 0 ≤ α < 1. We give conditions on f and M for this curve to be injective, and we show that this curve is continuous.

scholarly journals The strict topology on spaces of bounded holomorphic functions

1994 ◽  
Vol 49 (2) ◽  
pp. 249-256 ◽  
Author(s):  
Juan Ferrera ◽  
Angeles Prieto
Keyword(s):  
Banach Space ◽  
Unit Ball ◽  
Holomorphic Functions ◽  
Open Unit ◽  
Strict Topology ◽  
Open Unit Ball ◽  
Approximation By Polynomials ◽  
Bounded Holomorphic

We introduce in this paper the space of bounded holomorphic functions on the open unit ball of a Banach space endowed with the strict topology. Some good properties of this topology are obtained. As applications, we prove some results on approximation by polynomials and a description of the continuous homomorphisms.

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.

Geometry on the Unit Ball of a Complex Hilbert Space

1978 ◽  
Vol 30 (01) ◽  
pp. 22-31 ◽  
Author(s):  
Kyong T. Hahn
Keyword(s):  
Hilbert Space ◽  
Unit Ball ◽  
Hyperbolic Geometry ◽  
Complex Hilbert Space ◽  
Open Unit ◽  
Sufficient Condition ◽  
Necessary And Sufficient Condition ◽  
Open Unit Ball ◽  
Similar Role ◽  
Necessary And Sufficient

Furnishing the open unit ball of a complex Hilbert space with the Carathéodory-differential metric, we construct a model which plays a similar role as that of the Poincaré model for the hyperbolic geometry. In this note we study the question whether or not through a point in the model not lying on a given line there exists a unique perpendicular, and give a necessary and sufficient condition for the existence of a unique perpendicular. This enables us to divide a triangle into two right triangles. Many trigonometric identities in a general triangle are easy consequences of various identities which hold on a right triangle.

scholarly journals Homomorphisms between Algebras of Holomorphic Functions

2014 ◽  
Vol 2014 ◽  
pp. 1-12
Author(s):  
Verónica Dimant ◽  
Domingo García ◽  
Manuel Maestre ◽  
Pablo Sevilla-Peris
Keyword(s):  
Unit Ball ◽  
Banach Spaces ◽  
Entire Functions ◽  
Holomorphic Functions ◽  
Open Unit ◽  
Open Unit Ball ◽  
Generalized Spectrum ◽  
Algebras Of Holomorphic Functions ◽  
Algebra Homomorphisms ◽  
Bounded Holomorphic

For two complex Banach spacesXandY, in this paper, we study the generalized spectrumℳb(X,Y)of all nonzero algebra homomorphisms fromℋb(X), the algebra of all bounded type entire functions onX, intoℋb(Y). We endowℳb(X,Y)with a structure of Riemann domain overℒ(X*,Y*)wheneverXis symmetrically regular. The size of the fibers is also studied. Following the philosophy of (Aron et al., 1991), this is a step to study the setℳb,∞(X,BY)of all nonzero algebra homomorphisms fromℋb(X)intoℋ∞(BY)of bounded holomorphic functions on the open unit ball ofYandℳ∞(BX,BY)of all nonzero algebra homomorphisms fromℋ∞(BX)intoℋ∞(BY).

scholarly journals The Denjoy–Wolff Theorem in the Open Unit Ball of a Strictly Convex Banach Space

1999 ◽  
Vol 143 (1) ◽  
pp. 111-123 ◽  
Author(s):  
Jaroslaw Kapeluszny ◽  
Tadeusz Kuczumow ◽  
Simeon Reich
Keyword(s):  
Banach Space ◽  
Unit Ball ◽  
Convex Banach Space ◽  
Open Unit ◽  
Open Unit Ball ◽  
Strictly Convex ◽  
Strictly Convex Banach Space
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