Published Paper

Inserted: 16 may 2017
Last Updated: 16 may 2017

Journal: Real Analysis Exchange
Volume: 39
Number: 1
Pages: 45-56
Year: 2012

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.