English

Fine properties of Besov functions $B^r_{q,\infty}$ in metric spaces

Functional Analysis 2026-03-16 v1 Analysis of PDEs

Abstract

Let XX be a metric space and μ\mu an ss-regular Ahlfors measure. Let YY be a metric space. We prove that for Besov functions uBq,r(X,μ;Y)u \in B^r_{q,\infty}(X,\mu;Y), every point is a {\it general average Lebesgue point} of uu outside a σ\sigma-finite set with respect to the Hausdorff measure Hsrq\mathcal{H}^{s - rq}. The proof is based on density-type estimates involving Hausdorff measure. In addition, we prove that for functions uu in the fractional Sobolev space Wr,q(X,μ;Y)W^{r,q}(X,\mu;Y), almost every point with respect to Hsrq\mathcal{H}^{s - rq} is an {\it average Lebesgue point} of uu. Finally, if YY is also complete, we prove that for uBq,r(X,μ;Y)u \in B^r_{q,\infty}(X,\mu;Y), almost every point is a {\it Lebesgue point} outside a set of Hausdorff dimension at most srqs - rq.

Keywords

Cite

@article{arxiv.2603.12954,
  title  = {Fine properties of Besov functions $B^r_{q,\infty}$ in metric spaces},
  author = {Paz Hashash and Arkady Poliakovsky},
  journal= {arXiv preprint arXiv:2603.12954},
  year   = {2026}
}