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Related papers: Skew von Neumann constant in Weak Orlicz Spaces an…

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In this paper, we define a new geometric constant based on isosceles orthogonality, denoted by . Through research, we find that this constant is the equivalent p-th von Neumann Jordan constant in the sense of isosceles orthogonality. First,…

Functional Analysis · Mathematics 2025-06-17 Yuxin Wang , Qi Liu , Yongmo Hu , Jinyu Xia , Mengmeng Bao

Recently, the von Neumann-Jordan type constants C(X) has defined by Takahashi. A new skew generalized constant Cp({\lambda},\mu,X) based on C(X) constant is given in this paper. First, we will obtain some basic properties of this new…

Functional Analysis · Mathematics 2025-05-26 Yuxin Wang , Qi Liu , Yueyue Feng , Jinyu Xia , Muhammad Sarfraz

There are discussed some modifications of n-th von Neumann-Jordan constant considered by M. Kato, Y. Takahashi and K. Hashimoto. We study, among others, upper, lower, upper modified and lower modified n-th von Neumann-Jordan constant and…

Functional Analysis · Mathematics 2018-11-06 Maciej Ciesielski , Ryszard Płuciennik

This paper systematically investigates a new geometric constant associated with isosceles orthogonality in Banach spaces. By establishing the connection between this new constant and a classical function, sharp upper and lower bounds for…

Functional Analysis · Mathematics 2025-09-30 Tingting Hu , Qi Liu , Mengmeng Bao , Yuxin Wang

In this paper, we introduce a new constant for Banach spaces, denoted as $\widetilde{C}_{\mathrm{NJ}}^p(\xi, v, X)$. We provide calculations for both the lower and upper bounds of this constant, as well as its exact values in certain Banach…

Functional Analysis · Mathematics 2024-11-18 Yuxin Wang , Qi Liu , Jinyu Xia , Shuaizhe Huang

In this paper, several weak Orlicz-Hardy martingale spaces associated with concave functions are introduced, and some weak atomic decomposition theorems for them are established. With the help of weak atomic decompositions, a sufficient…

Functional Analysis · Mathematics 2013-04-16 Yong Jiao , Lian Wu

We provide necessary and sufficient conditions for the coincidence, up to equivalence of the norms, between strong and weak Orlicz spaces. Roughly speaking, this coincidence holds true only for the so-called exponential spaces. We find also…

Functional Analysis · Mathematics 2019-01-01 Maria Rosaria Formica , Eugeny Ostrovsky

Empirical studies have widely demonstrated that neural networks are highly sensitive to small, adversarial perturbations of the input. The worst-case robustness against these so-called adversarial examples can be quantified by the Lipschitz…

Machine Learning · Statistics 2025-07-03 Paul Geuchen , Dominik Stöger , Thomas Telaar , Felix Voigtlaender

Density of Lipschitz functions in Newtonian spaces based on quasi-Banach function lattices is discussed. Newtonian spaces are first-order Sobolev-type spaces on abstract metric measure spaces defined via (weak) upper gradients. Our main…

Functional Analysis · Mathematics 2014-04-29 Lukáš Malý

In this article, we introduce a novel geometric constant $L_X(t)$, which provides an equivalent definition of the von Neumann-Jordan constant from an orthogonal perspective. First, we present some fundamental properties of the constant…

Functional Analysis · Mathematics 2025-04-02 Qichuan Ni , Qi Liu , Yuxin Wang , Jinyu Xia , Ranran Wang

In this paper we discuss the structure of weighted weak Lebesgue spaces and weighted weak Orlicz spaces on $\mathbb{R}^n$. First, we present sufficient and necessary conditions for inclusion relation between weighted weak Lebesgue spaces.…

Functional Analysis · Mathematics 2017-10-13 Al Azhary Masta , Ifronika , Muhammad Taqiyuddin

In this paper, we consider the predual spaces of weak Orlicz spaces. As an application, we provide the Fefferman-Stein vector-valued maximal inequality for the weak Orlicz spaces. In order to prove this statement, we introduced the…

Functional Analysis · Mathematics 2021-04-27 Naoya Hatano , Ryota Kawasumi , Takahiro Ono

Properties of first-order Sobolev-type spaces on abstract metric measure spaces, so-called Newtonian spaces, based on quasi-Banach function lattices are investigated. The set of all weak upper gradients of a Newtonian function is of…

Functional Analysis · Mathematics 2013-08-14 Lukáš Malý

In the past, Takahashi has introduced the James type constants $\mathcal{J}_{\mathcal{X} ,t}(\tau)$. Building upon this foundation, we introduce an innovative skew James type constant, denoted as $\mathcal{J}_t[\tau,\mathcal{X}]$, which is…

Functional Analysis · Mathematics 2025-04-02 Zhiyong Rao , Qi Liu , Qiong Wu , Zhouping Yin , Qichuan Ni

We prove some results on weakly almost square Banach spaces and their relatives. On the one hand, we discuss weak almost squareness in the setting of Banach function spaces. More precisely, let $(\Omega,\Sigma)$ be a measurable space, let…

Functional Analysis · Mathematics 2023-01-20 José Rodríguez , Abraham Rueda Zoca

We establish a weighted $L^p$ norm estimate for the Bergman projection for a class of pseudoconvex domains. We obtain an upper bound for the weighted $L^p$ norm when the domain is, for example, a bounded smooth strictly pseudoconvex domain,…

Complex Variables · Mathematics 2023-10-18 Zhenghui Huo , Nathan A. Wagner , Brett D. Wick

We prove a Payne-Weinberger type inequality for the $p$-Laplacian Neumann eigenvalues ($p\ge 2$). The inequality provides the sharp upper bound on convex domains, in terms of the diameter alone, of the best constants in Poincar\'e…

Analysis of PDEs · Mathematics 2011-10-14 L. Esposito , C. Nitsch , C. Trombetti

In this paper we focus on the relation between Riemann integrability and weak continuity. A Banach space $X$ is said to have the weak Lebesgue property if every Riemann integrable function from $[0,1]$ into $X$ is weakly continuous almost…

Functional Analysis · Mathematics 2015-10-30 Gonzalo Martínez-Cervantes

For any $\lambda>1, R_\lambda^2$ is Bana\'s-Fr\k{a}czek space, the exact value of the skew generalized von Neumann-Jordan constant $C_{\mathrm{NJ}}^p\left(\xi, \eta, R_\lambda^2\right)$ is calculated. By careful calculations,…

Functional Analysis · Mathematics 2024-12-17 Linhui Chen , Qi Liu , Xiewei Tan , Yuxin Wang

In this paper, combined with the P-angle function of Banach spaces and the geometric constants that can characterize Hilbert spaces, the new angular geometric constant is defined. Firstly, this paper explores the basic properties of the new…

Functional Analysis · Mathematics 2022-08-25 Zhijian Yang , Yongjin Li
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