期刊名称：International Journal of Mathematics and Mathematical Sciences
印刷版ISSN：0161-1712
电子版ISSN：1687-0425
出版年度：2009
卷号：2009
DOI：10.1155/2009/573038
出版社：Hindawi Publishing Corporation
摘要：A topological space (𝑋,𝜏) is said to be strongly compact if every preopen cover of (𝑋,𝜏) admits a finite subcover. In this paper, we introduce a new class of sets called 𝒩-preopen sets which is weaker than both open sets and 𝒩-open sets. Where a subset 𝐴
is said to be 𝒩-preopen if for each 𝑥∈𝐴
there exists a preopen set 𝑈𝑥
containing 𝑥 such that 𝑈𝑥−𝐴 is a finite
set. We investigate some properties of the sets. Moreover, we obtain new characterizations and preserving theorems of strongly compact spaces.
