中文

度量空间上Sobolev空间与常数函数的表征

泛函分析 2026-02-09 v3

摘要

在满足Poincaré不等式的双倍度量测度空间(X,ρ,μ)(X,\rho,\mu)中,我们给出一种以均衡振荡为依据的第一阶Sobolev空间的新表征,并通过一种新方法扩展了关于常数函数表征的既有结果。作为独立势能工具,我们引入一种新的“宏观”Poincaré不等式,其右侧的振荡形式与左侧相同,但尺度更小,取值为r(0,R)r\in(0,R)。除了内在的数学兴趣外,这些结果还源于对算子 [f,T][f,T](由点态乘子和奇异积分组成)在定量紧凑性质上的应用。充分利用这些结果后,可在同一类一般域(X,ρ,μ)(X,\rho,\mu)上获得算子映射性质的表征,这一结果将在另一篇伴随论文中详述。

关键词

引用

@article{arxiv.2508.07801,
  title  = {Characterisations of Sobolev spaces and constant functions over metric spaces},
  author = {Tuomas Hytönen and Riikka Korte},
  journal= {arXiv preprint arXiv:2508.07801},
  year   = {2026}
}

备注

Previously Part I of the long paper arXiv:2411.02613v1, we have extracted this independent entity into this separate paper. V2: 31 pages. Some digressions removed from the Introduction, added new Section 10. V3: Introduction rewritten, a stronger version of the characterisation of constants with a new Corollary 4.6 in the Bessel setting