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Related papers: Banach function spaces done right

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Inspired by the recent work of Cascales et al., we introduce a generalized concept of ACK structure on Banach spaces. Using this property, which we call by the quasi-ACK structure, we are able to extend known universal properties on range…

Functional Analysis · Mathematics 2023-03-27 Geunsu Choi , Mingu Jung

We show that there exist infinite-dimensional extremely non-complex Banach spaces, i.e. spaces $X$ such that the norm equality $\|Id + T^2\|=1 + \|T^2\|$ holds for every bounded linear operator $T:X\longrightarrow X$. This answers in the…

Functional Analysis · Mathematics 2008-11-26 Piotr Koszmider , Miguel Martin , Javier Meri

Here we give a necessary and sufficient condition for a Banach space to be separable.

Functional Analysis · Mathematics 2007-05-23 K. Gowri Navada

As objects of study in functional analysis, Hilbert spaces stand out as special objects of study as do nuclear spaces in view of a rich geometrical structure they possess as Banach and Frechet spaces, respectively. On the other hand, there…

Functional Analysis · Mathematics 2013-10-29 M A Sofi

We construct various examples of Sobolev-type functions, defined via upper gradients in metric spaces, that fail to be quasicontinuous or weakly quasicontinuous. This is done with quasi-Banach function lattices $X$ as the function spaces…

Functional Analysis · Mathematics 2025-03-28 Anders Björn , Jana Björn , Lukáš Malý

In this paper we propose a general coorbit space theory suitable to define coorbits of quasi-Banach spaces using an abstract continuous frame, indexed by a locally compact Hausdorff space, and an associated generalized voice transform. The…

Functional Analysis · Mathematics 2016-08-31 Henning Kempka , Martin Schäfer , Tino Ullrich

Kalton and Mitrea characterized complex interpolation spaces of quasi-Banach function spaces as Calder\'on products if both interpolants are separable. We show that one separability assumption may be omitted and establish a…

Functional Analysis · Mathematics 2024-12-18 Moritz Egert , Benjamin W. Kosmala

Let $X$ and $Y$ be Banach spaces such that the ideal of operators which factor through $Y$ has codimension one in the Banach algebra $\mathscr{B}(X)$ of all bounded operators on $X$, and suppose that $Y$ contains a complemented subspace…

K-Theory and Homology · Mathematics 2015-04-06 Tomasz Kania , Piotr Koszmider , Niels Jakob Laustsen

In this survey, we consider Banach spaces of analytic functions in one and several complex variables for which: (i) polynomials are dense, (ii) point-evaluations on the domain are bounded linear functionals, and (iii) the shift operator…

Functional Analysis · Mathematics 2025-04-23 Jeet Sampat

In this note we study Banach spaces of traces of real polynomials on $\mathbb R^n$ to compact subsets equipped with supremum norms from the point of view of Geometric Functional Analysis.

Functional Analysis · Mathematics 2014-04-23 Alexander Brudnyi

In this paper, we study the existence of the random approximations and fixed points for random almost lower semicontinuous operators defined on finite dimensional Banach spaces, which in addition, are condensing or 1-set-contractive. Our…

Probability · Mathematics 2015-07-13 Monica Patriche

In [3] it was proved that almost-greedy and semi-greedy bases are equivalent in the context of Banach spaces with finite cotype. In this paper we show this equivalence for general Banach spaces.

Functional Analysis · Mathematics 2018-06-19 Pablo M. Berná

We develop a microspectral theory for quasinilpotent linear operators $Q$ (i.e., those with $\sigma(Q) = \{0}$) in a Banach space. When such $Q$ is not compact, normal, or nilpotent, the classical spectral theory gives little information,…

Spectral Theory · Mathematics 2012-11-21 Jarmo Malinen , Olavi Nevanlinna , Jaroslav Zemánek

We introduce the concept of an $E$-valued function algebra, a type of Banach algebra that consist of continuous $E$-valued functions on some compact Hausdorff space, where $E$ is a Banach algebra. We present some basic results about such…

Functional Analysis · Mathematics 2020-08-12 Azadeh Nikou , Anthony G. O'Farrell

We obtain new uniqueness theorems for harmonic functions defined on the unit disc or in the half plane. These results are applied to obtain new resolvent descriptions of spectral subspaces of polynomially bounded groups of operators on…

Complex Variables · Mathematics 2010-03-16 Alexander Borichev , Yuri Tomilov

We produce several situations where some natural subspaces of classical Banach spaces of functions over a compact abelian group contain the space $c_0$.

Functional Analysis · Mathematics 2009-12-17 Pascal Lefèvre , Daniel Li , Hervé Queffélec , Luis Rodriguez-Piazza

The concept of a quasi-metric space arises by relaxing the requirement of the symmetry axiom in the definition of a metric. This small variation alters several structural properties possessed by a standard metric space. This article aims to…

General Topology · Mathematics 2025-11-21 Om Dev Singh , Anubha Jindal

We prove implicit function theorems for mappings on topological vector spaces over valued fields. In the real and complex cases, we obtain implicit function theorems for mappings from arbitrary (not necessarily locally convex) topological…

General Mathematics · Mathematics 2007-05-23 Helge Glockner

We show examples of compact linear operators between Banach spaces which cannot be approximated by norm attaining operators. This is the negative answer to an open question posed in the 1970's. Actually, any strictly convex Banach space…

Functional Analysis · Mathematics 2014-07-16 Miguel Martin

Similar to linear spaces, many examples of quasilinear spaces have a notion of multiplication of the elements. To characterising these examples, in the present paper we generalize the notion of quasilinear spaces and introduce…

Functional Analysis · Mathematics 2020-10-20 Reza Dehghanizade , Seyed Mohamad Sadegh Modarres Mosadegh