Dachun Yang

activity

20242026

collaborators

11 papers

math.FA2026

A Sharp Localized Weighted Inequality Related to Gagliardo and Sobolev Seminorms and Its Applications

Pingxu Hu, Yinqin Li, Dachun Yang +1

In this article, we establish a nearly sharp localized weighted inequality related to Gagliardo and Sobolev seminorms, respectively, with the sharp $A_{1}$ -weight constant or with th…

math.FA2025

Maz'ya--Shaposhnikova Representation of Quasi-Norms of Ball Quasi-Banach Function Spaces on Spaces of Homogeneous Type with Weak Reverse Doubling Property

Eiichi Nakai, Menghao Tang, Dachun Yang +2

Let $Y (X)$ be a ball quasi-Banach function space on the space of homogeneous type $(X, ρ, μ)$ satisfying some mild additional assumptions, $q \in (0, \infty)$ , and $…

math.FA2025

Matrix-Weighted Campanato Spaces: Duality and Calderón--Zygmund Operators

Yiqun Chen, Dachun Yang, Wen Yuan

Let $p \in (0, \infty)$ , $q \in [1, \infty)$ , $s \in Z_{+}$ , and $W$ be an $A_{p}$ -matrix weight, which in the scalar case is exactly a Muckenhoupt $A_{m a x {1, p}}$ weight. In this ar…

math.FA2025

Characterization of Vanishing Campanato Spaces via Ball Banach Function Spaces and Its Applications

Xing Fu, Yoshihiro Sawano, Jin Tao +1

In this article, the authors provide some new characterizations of several vanishing Campanato spaces using a type of oscillation defined within the general framework of ball Banac…

math.FA2025

Difference and Wavelet Characterizations of Distances from Functions in Lipschitz Spaces to Their Subspaces

Feng Dai, Eero Saksman, Dachun Yang +2

Let $Λ_{s}$ denote the Lipschitz space of order $s \in (0, \infty)$ on $R^{n}$ , which consists of all $f \in C \cap L^{\infty}$ such that, for some constant $L\in(0,\infty)…

math.FA2025

Sharp Brezis--Seeger--Van Schaftingen--Yung Formulae for Higher-Order Gradients in Ball Banach Function Spaces

Pingxu Hu, Yinqin Li, Dachun Yang +2

Let $X$ be a ball Banach function space on $R^{n}$ , $k \in N$ , $h \in R^{n}$ , and $Δ_{h}^{k}$ denote the $k$ {\rm th} order difference. In this article, under some mi…