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We obtain estimates in the corona theorem for the algebra of analytic functions in the unit disc whose nth derivative is bounded, and its subalgebras defined by the boundary continuity of the nth derivative. The corona theorem for such…

Classical Analysis and ODEs · Mathematics 2010-07-08 Amol Sasane , Sergei Treil

It is shown that if $A$ is a uniform algebra generated by real-analytic functions on a suitable compact subset $K$ of a real-analytic variety such that the maximal ideal space of $A$ is $K$, and every continuous function on $K$ is locally a…

Complex Variables · Mathematics 2016-12-28 John T. Anderson , Alexander J. Izzo

We study the Banach algebras of bounded holomorphic functions on the unit disk whose boundary values, having, in a sense, the weakest possible discontinuities, belong to the algebra of semi-almost periodic functions on the unit circle. The…

Complex Variables · Mathematics 2009-11-06 A. Brudnyi , D. Kinzebulatov

We construct differential algebras in which spaces of (one-dimensional) periodic ultradistributions are embedded. By proving a Schwartz impossibility type result, we show that our embeddings are optimal in the sense of being consistent with…

Functional Analysis · Mathematics 2017-10-12 Andreas Debrouwere

We study the structure of the maximal ideal space $M(H^{\infty})$ of the algebra $H^{\infty}=H^{\infty}(\Di)$ of bounded analytic functions defined on the open unit disk $\Di\subset\Co$. Based on the fact that $dim\ M(H^{\infty})=2$ we…

Complex Variables · Mathematics 2007-05-23 Alexander Brudnyi

We consider composite functions in the elementary algebraic framework. Without any use of the Fourier transform, we find almost periodic orbits which suitably characterizes certain composite functions. In particular, we provide special…

Machine Learning · Computer Science 2025-06-17 Chikara Nakayama , Tsuyoshi Yoneda

We study some topological properties of maximal ideal spaces of certain algebras of almost periodic functions. Our main result is that such spaces are contractible. We present certain corollaries of this result.

Functional Analysis · Mathematics 2007-05-23 A. Brudnyi

We give characterizations of unital uniform topological algebras and saturated locally multiplicatively convex algebras by means of multiplicative linear functionals. Some automatic continuity theorems in advertibly complete uniform…

Functional Analysis · Mathematics 2014-01-03 M. El Azhari

We present a unified theory for the almost periodicity of functions with values in an arbitrary Banach space, measures and distributions via almost periodic elements for the action of a locally compact abelian group on a uniform topological…

Functional Analysis · Mathematics 2022-08-03 Daniel Lenz , Timo Spindeler , Nicolae Strungaru

The most important uniform algebra is the family of continuous functions on a compact subset $K$ of the complex plane $\mathbb{C}$ which are analytic on the interior int$(K)$ For compact sets $K$ which are regular (i.e. $K =$int$(K)$ and…

Complex Variables · Mathematics 2019-05-08 Abtin Daghighi , Paul M. Gauthier

Let $\mathbb{I}$ be a proper ideal of $H^{\infty}(\D)$. We prove the corona theorem for infinitely many generators on the algebra $H^{\infty}_{\mathbb{I}}$ in which the corona theorem for finitely many functions is known to hold. This…

Functional Analysis · Mathematics 2017-02-28 Debendra P. Banjade

Given a complex domain $\Omega$ and analytic functions $\varphi_1,\ldots,\varphi_n : \Omega \to \mathbb{D}$, we give geometric conditions for $H^\infty(\Omega)$ to be generated by functions of the form $g \circ \varphi_k$, $g \in…

Complex Variables · Mathematics 2017-03-22 Michael A. Dritschel , Daniel Estévez , Dmitry Yakubovich

Using a description of the spectrum of bidual algebra $A^{**}$ of a uniform algebra $A$ we obtain abstract corona theorem for certain uniform algebras. It asserts the density of a specific Gleason part in the spectrum of an $H^\infty$ --…

Functional Analysis · Mathematics 2026-03-24 Marek Kosiek , Krzysztof Rudol

For a wide class of domains $G\subset\mathbb C^d$ including balls and polydisks we prove the density of their canonical image in the spectrum of $H^\infty(G)$. This Corona Theorem is proved first in its abstract version for certain uniform…

Functional Analysis · Mathematics 2025-05-27 Marek Kosiek , Krzysztof Rudol

In the study of the cyclicity of a function $f$ in reproducing kernel Hilbert spaces an important role is played by sequences of polynomials $\{p_n\}_{n\in \mathbb{N}}$ called \emph{optimal polynomial approximants} (o.p.a.). For many such…

Complex Variables · Mathematics 2021-10-14 Antonio Acuaviva , Daniel Seco

Let $PQC$ stand for the set of all piecewise quasicontionus function on the unit circle, i.e., the smallest closed subalgebra of $L^\infty(\mathbb{T})$ which contains the classes of all piecewise continuous function $PC$ and all…

Functional Analysis · Mathematics 2017-12-06 Torsten Ehrhardt , Zheng Zhou

Using the notion of complete compactness introduced by H. Saar, we define completely almost periodic functionals on completely contractive Banach algebras. We show that, if $(M,\Gamma)$ is a Hopf--von Neumann algebra with $M$ injective,…

Functional Analysis · Mathematics 2011-11-17 Volker Runde

We prove the generalized Wolff's Ideal Theorem on certain uniformly closed subalgebras of $ H^{\infty}(\mathbb{D}) $ on which the Corona Theorem is already known to hold.

Functional Analysis · Mathematics 2015-07-29 Debendra Banjade , Caleb Holloway , Tavan Trent

The almost periodic functions form a natural example of a non-separable normed space. As such, it has been a challenge for constructive mathematicians to find a natural treatment of them. Here we present a simple proof of Bohr's fundamental…

Logic in Computer Science · Computer Science 2017-01-11 Bas Spitters

In this paper we study weakly almost periodic and uniformly continuous functionals on the Orlicz Fig\`a-Talamanca Herz algebras associated to a locally compact group. We show that a unique invariant mean exists on the space of weakly almost…

Functional Analysis · Mathematics 2019-09-16 Rattan Lal , N. Shravan Kumar
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