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Related papers: A numerical range approach to Birkhoff-James ortho…

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We study the local preservation of Birkhoff-James orthogonality by linear operators between normed linear spaces, at a point and in a particular direction. We obtain a complete characterization of the same, which allows us to present…

Functional Analysis · Mathematics 2025-01-07 Jayanta Manna , Kalidas Mandal , Kallol Paul , Debmalya Sain

The purpose of this paper is to study an implicit scheme for a representation of nonexpansive mappings on a closed convex subset of a smooth and uniformly convex Banach space with respect to a left regular sequence of means defined on an…

Functional Analysis · Mathematics 2015-06-10 Ebrahim Soori

Well known to the machine learning community, the random feature model is a parametric approximation to kernel interpolation or regression methods. It is typically used to approximate functions mapping a finite-dimensional input space to…

Numerical Analysis · Mathematics 2022-06-23 Nicholas H. Nelsen , Andrew M. Stuart

We investigate $\rho$-orthogonality and its local symmetry in the space of bounded linear operators. A characterization of Hilbert space operators with symmetric numerical range is established in terms of $\rho$-orthogonality. Further, we…

Functional Analysis · Mathematics 2025-12-15 Souvik Ghosh , Kallol Paul , Debmalya Sain

In this paper, first we present a new useful way of formulating probabilistic normed spaces. Then by using this formulation and probabilistic normed space version of the Baire category theorem, we prove four important results of functional…

Functional Analysis · Mathematics 2018-07-10 Delavar Varasteh Tafti , Mahdi Azhini

This paper introduces statistical order convergence and its pointwise variant for sequences of order bounded operators between Riesz spaces. We establish fundamental properties: uniqueness of the limit, stability under lattice operations,…

Functional Analysis · Mathematics 2025-12-30 Abdullah Aydın , Erdal Bayram , İshak Aydın

In this paper, we introduce a class of backward stochastic equations (BSEs) that extend classical BSDEs and include many interesting examples of generalized BSDEs as well as semimartingale backward equations. We show that a BSE can be…

Probability · Mathematics 2017-03-28 Patrick Cheridito , Kihun Nam

We study the relation between the spectrum of a self-adjoint operator and its multidimensional numerical range. It turns out that the multidimensional numerical range is a convex set whose extreme points are sequences of eigenvalues of the…

Spectral Theory · Mathematics 2007-05-23 Yuri Safarov

The main aim of this work is to give a general approach to the celebrated Kahane-Salem-Zygmund inequalities. We prove estimates for exponential Orlicz norms of averages $\sup_{1\le j \leq N} \big |\sum_{1 \leq i \leq K}\gamma_i(\cdot)…

Functional Analysis · Mathematics 2020-08-12 Andreas Defant , Mieczysław Mastyło

In this paper, we generalize the notions of numerical radius parallelism and numerical radius Birkhoff orthogonality, originally formulated for operators on Hilbert spaces, to operators on normed spaces. We then proceed to demonstrate their…

Functional Analysis · Mathematics 2024-12-03 Jiaye Bi , Huayou Xie , Yongjin Li

This work will be centered in commutative Banach subalgebras of the algebra of bounded linear operators defined on a Free Banach spaces of countable type. The main goal of this work wil be to formulate a representation theorem for these…

Functional Analysis · Mathematics 2017-07-25 José Aguayo , Miguel Nova , Jacqueline Ojeda

The aim of this paper is to establish strong convergence theorems for a strongly relatively nonexpansive sequence in a smooth and uniformly convex Banach space. Then we employ our results to approximate solutions of the zero point problem…

Functional Analysis · Mathematics 2020-12-29 Koji Aoyama , Yasunori Kimura , Fumiaki Kohsaka

We construct an example of a real Banach space whose group of surjective isometries has no uniformly continuous one-parameter semigroups, but the group of surjective isometries of its dual contains infinitely many of them. Other examples…

Functional Analysis · Mathematics 2008-11-05 Miguel Martin

We study the James constant $J(\mathbb{X})$, an important geometric quantity associated with a normed space $ \mathbb{X} $, and explore its connection with isosceles orthogonality $ \perp_I. $ The James constant is defined as $J(\mathbb{X})…

Functional Analysis · Mathematics 2024-08-14 Debmalya Sain , Souvik Ghosh , Kallol Paul

Here we consider two notions of mappings of bounded variation (BV) from the metric measure space into the metric space; one based on relaxations of Newton-Sobolev functions, and the other based on a notion of AM-upper gradients. We show…

Metric Geometry · Mathematics 2023-08-22 Ivan Caamano , Josh Kline , Nageswari Shanmugalingam

We call a bounded linear operator acting between Banach spaces weakly compactly generated ($\mathsf{WCG}$ for short) if its range is contained in a weakly compactly generated subspace of its codomain. This notion simultaneously generalises…

Functional Analysis · Mathematics 2014-11-26 Tomasz Kania , Tomasz Kochanek

Motivated by a variety of representations of fractional powers of operators, we develop the theory of abstract Besov spaces $B^{ s, A }_{ q, X }$ for non-negative operators $A$ on Banach spaces $X$ with a full range of indices $s \in…

Functional Analysis · Mathematics 2020-06-15 Charles Batty , Chuang Chen

We study $k-$smoothness of bounded linear operators defined between arbitrary Banach spaces. As an application, we characterize $k-$smooth operators defined from $\ell_1^n$ to an arbitrary Banach space. We also completely characterize…

Functional Analysis · Mathematics 2019-09-05 Arpita Mal , Kallol Paul

Classic subdifferentials in variational analysis may fail to fully represent the Bregman proximal operator in the absence of convexity. In this paper, we fill this gap by introducing the left and right \emph{Bregman level proximal…

Optimization and Control · Mathematics 2026-04-14 Ziyuan Wang , Andreas Themelis

For a bounded linear operator on a Banach space, we study approximation of the spectrum and pseudospectra in the Hausdorff distance. We give sufficient and necessary conditions in terms of pointwise convergence of appropriate spectral…

Functional Analysis · Mathematics 2022-09-12 Marko Lindner , Dennis Schmeckpeper