English

Directional Lower Porosity

Functional Analysis 2014-08-29 v1 Classical Analysis and ODEs Metric Geometry

Abstract

We investigate differences between upper and lower porosity. In finite dimensional Banach spaces every upper porous set is directionally upper porous. We show the situation is very different for lower porous sets; there exists a lower porous set in the plane which is not even a countable union of directionally lower porous sets.

Keywords

Cite

@article{arxiv.1209.4491,
  title  = {Directional Lower Porosity},
  author = {Gareth Speight},
  journal= {arXiv preprint arXiv:1209.4491},
  year   = {2014}
}

Comments

8 pages

R2 v1 2026-06-21T22:08:24.073Z