English

BMO on shapes and sharp constants

Functional Analysis 2019-05-02 v1

Abstract

We consider a very general definition of BMO on a domain in Rn\mathbb{R}^n, where the mean oscillation is taken with respect to a basis of shapes, i.e. a collection of open sets covering the domain. We examine the basic properties and various inequalities that can be proved for such functions, with special emphasis on sharp constants. For the standard bases of shapes consisting of balls or cubes (classic BMO), or rectangles (strong BMO), we review known results, such as the boundedness of rearrangements and its consequences. Finally, we prove a product decomposition for BMO when the shapes exhibit some product structure, as in the case of strong BMO.

Keywords

Cite

@article{arxiv.1905.00144,
  title  = {BMO on shapes and sharp constants},
  author = {Galia Dafni and Ryan Gibara},
  journal= {arXiv preprint arXiv:1905.00144},
  year   = {2019}
}
R2 v1 2026-06-23T08:53:57.459Z