定向下孔隙度
Directional Lower Porosity
摘要：
我们研究了上部和下部孔隙度之间的差异。在有限维巴拿赫空间中，每个上多孔集都是方向上多孔集.我们的情况是非常不同的低多孔集，存在一个低多孔集在平面上，甚至不是一个可数的联盟定向低多孔集。
英文摘要：
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.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
