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Related papers: Operator ideals associated with the Szlenk index

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We prove the regularity of the $\eta$ function for classical pseudodifferential operators with Shubin symbols. We recall the construction of complex powers and of the Wodzicki and Kontsevich-Vishik functionals for classical symbols on…

Operator Algebras · Mathematics 2012-09-07 Pedro Lopes

An operator system $\cl S$ with unit $e$, can be viewed as an Archimedean order unit space $(\cl S,\cl S^+,e)$. Using this Archimedean order unit space, for a fixed $k\in \bb N$ we construct a super k-minimal operator system OMIN$_k(\cl S)$…

Operator Algebras · Mathematics 2011-11-15 Blerina Xhabli

For each ordinal $\alpha<\omega_1$, we introduce the class of $\alpha$-balanced Polish groups. These classes form a hierarchy that completely stratifies the space between the class of Polish groups admitting a two-side-invariant metric…

Logic · Mathematics 2026-05-07 Shaun Allison , Aristotelis Panagiotopoulos

Denote by $[0,\omega_1)$ the set of countable ordinals, equipped with the order topology, let $L_0$ be the disjoint union of the compact ordinal intervals $[0,\alpha]$ for $\alpha$ countable, and consider the Banach spaces $C_0[0,\omega_1)$…

Functional Analysis · Mathematics 2015-04-28 Tomasz Kania , Niels Jakob Laustsen

The primary objective of this paper is to investigate the orthonormal Strichartz estimates at the critical summability exponent for the Schr\"odinger operator $e^{it\Delta}$ with initial data from the homogeneous Sobolev space $\dot{H}^s…

Analysis of PDEs · Mathematics 2025-07-22 Guoxia Feng , Manli Song , Huoxiong Wu

In this note, we will discuss how to relate an operator ideal on Banach spaces to the sequential structures it defines. Concrete examples of ideals of compact, weakly compact, completely continuous, Banach-Saks and weakly Banach-Saks…

Functional Analysis · Mathematics 2011-01-12 Ngai-Ching Wong

In addition to Pisier's counterexample of a non-accessible maximal Banach ideal, we will give a large class of maximal Banach ideals which {\it{are accessible}}. The first step is implied by the observation that a "good behaviour" of trace…

Functional Analysis · Mathematics 2016-09-06 Frank Oertel

The work of Dykema, Figiel, Weiss, and Wodzicki on the structure of commutators showed that arithmetic means play an important role in the study of operator ideals, and we explored their role in a multipaper project which we survey in this…

Functional Analysis · Mathematics 2007-07-24 Victor Kaftal , Gary Weiss

For $\delta$ an $m$-tuple of analytic functions, we define an algebra $\hidg$, contained in the bounded analytic functions on the analytic polyhedron $ {|\delta^l(z)| < 1, \ 1 \leq l \leq m}$, and prove a representation formula for it. We…

Complex Variables · Mathematics 2012-12-24 Jim Agler , John E. McCarthy

We study the unitary orbit of a normal operator $a\in \mathcal B(\mathcal H)$, regarded as a homogeneous space for the action of unitary groups associated with symmetrically normed ideals of compact operators. We show with an unified…

Functional Analysis · Mathematics 2021-11-09 Daniel Beltita , Gabriel Larotonda

Let $A$ be a square matrix and let $\Omega$ be an open set in the plane containing the spectrum of $A$. We consider the problem of maximizing the operator norm $\|f(A)\|$ amongst all holomorphic functions $f$ from $\Omega$ into the closed…

Spectral Theory · Mathematics 2020-11-06 Thomas Ransford , Nathan Walsh

Let $L=-\Delta+V$ be a Schr\"{o}dinger operator, where $\Delta $ is the Laplacian operator on $\rz$, while nonnegative potential $V$ belongs to the reverse H\"{o}lder class. In this paper, we establish the weighted norm inequalities for…

Functional Analysis · Mathematics 2011-09-02 Lin Tang

In this article, we conduct a study of integral operators defined in terms of non-convolution type kernels with singularities of various degrees. The operators that fall within our scope of research include fractional integrals, fractional…

Functional Analysis · Mathematics 2018-01-16 Lucas Chaffee , Jarod Hart , Lucas Oliveira

We study automatic injectivity of surjective algebra homomorphisms from $\mathscr{B}(X)$, the algebra of (bounded, linear) operators on $X$, to $\mathscr{B}(Y)$, where $X$ is one of the following \emph{long} sequence spaces: $c_0(\lambda)$,…

Functional Analysis · Mathematics 2021-12-13 Bence Horváth , Tomasz Kania

We consider semi-infinite Jacobi matrices corresponding to a point interaction for the discrete Schr\"odinger operator. Our goal is to find explicit expressions for the spectral measure, the resolvent and other spectral characteristics of…

Spectral Theory · Mathematics 2018-01-03 D. R. Yafaev

We prove that any normalized block sequence in a Schreier space $X_\xi$, of arbitrary order $\xi<\omega_1$, admits a subsequence equivalent to a subsequence of the canonical basis of some Schreier space. The analogous result is proved for…

Functional Analysis · Mathematics 2023-11-16 R. M. Causey , A. Pelczar-Barwacz

Theorem A and Theorem B of [1] state that for $1<p<\infty$ the lattice of closed ideals of $\mathcal{L}(\ell_p,c_0)$, $\mathcal{L}(\ell_p,\ell_\infty)$ and of $\mathcal{L}(\ell_1,\ell_p)$ are at least of cardinality $2^{\omega}$. Here we…

Functional Analysis · Mathematics 2021-01-06 Daniel Freeman , Thomas Schlumprecht , Andras Zsak

It is well known that the only proper non-trivial norm-closed ideal in the algebra L(X) for X=\ell_p (1 \le p < \infty) or X=c_0 is the ideal of compact operators. The next natural question is to describe all closed ideals of…

Functional Analysis · Mathematics 2007-06-13 B. Sari , Th. Schlumprecht , N. Tomczak-Jaegermann , V. G. Troitsky

In the framework of operator theory, we investigate a close Lie theoretic relationship between all operator ideals and certain classical groups of invertible operators that can be described as the solution sets of certain algebraic…

Operator Algebras · Mathematics 2013-03-21 Daniel Beltita , Sasmita Patnaik , Gary Weiss

This paper, being the sequel of [An inverse problem in Polya-Schur theory. I. Non-genegerate and degenerate operators], studies a class of linear ordinary differential operators with polynomial coefficients called \emph{exactly solvable};…

Dynamical Systems · Mathematics 2024-12-03 Per Alexandersson , Nils Hemmingsson , Boris Shapiro
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