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arXiv · 1209.4491

Directional Lower Porosity

Gareth Speight
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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.

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Gareth Speight. 2012-09-20. Directional Lower Porosity. https://arxiv.org/abs/1209.4491

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