collaborators

5 papers

math.FA2026

Weak-type characterizations of Sobolev and bounded variation spaces on metric measure spaces

Tuomas P. Hytönen, Dachun Yang, Wen Yuan +1

Given a complete doubling metric measure space supporting a Poincaré inequality, we prove weak-type characterizations of the Sobolev space and the spac…

math.CA2026

Fractional Gagliardo--Nirenberg Inequalities: Pointwise Estimates,Sharp Asymptotics, and Optimal Target Spaces

Pingxu Hu, Yinqin Li, Dachun Yang +1

We establish two pointwise estimates for fractional difference operators, tracking explicitly the dependence of the constants on the smoothness index . Using these, with…

math.CA2026

Optimal Weak-Type Estimates and Their Applications of Lifted Rough Maximal Operators

Dachun Yang, Wen Yuan, Yirui Zhao

Let and with . In this article, we introduce a new family of lifted rough maximal operators $\{\mathcal{M…

math.CA2025

Sharp Weighted Cohen--Dahmen--Daubechies--DeVore Inequality with Applications to (Weighted) Critical Sobolev Spaces, Gagliardo--Nirenberg Inequalities, and Muckenhoupt Weights

Yinqin Li, Dachun Yang, Wen Yuan +2

In this article, we establish a quantitative weighted variant of a far-reaching inequality obtained by A. Cohen, W. Dahmen, I. Daubechies, and R. DeVore in 2003, whose dependence o…

math.FA2025

Besov--Triebel--Lizorkin-Type Spaces with Matrix Weights

Fan Bu, Tuomas Hytönen, Dachun Yang +1

Introduced by A. Volberg, matrix weights provide a suitable generalization of Muckenhoupt weights from the classical theory. In our previous work, we esta…