合肥学院学报:自然科学版
閤肥學院學報:自然科學版
합비학원학보:자연과학판
Journal of Hefei University :Natural Sciences
2012年
3期
14-16
,共3页
几乎亚紧%基-亚紧%基-仿紧%点有限
幾乎亞緊%基-亞緊%基-倣緊%點有限
궤호아긴%기-아긴%기-방긴%점유한
nearly metacompact%base-metacompact%base-paracompact%point-finite
通过介绍几乎基一亚紧定义,研究了几乎基一亚紧空间,得到如下结论:(1)若X是可数个相对于X是几乎基一亚紧的闭集的并,则X是几乎基-亚紧的;(2)空间X是几乎基一亚紧的,当且仅当它有一个开基B,且|B|=w(X),和一个稠密子集D∈X,使得对X的每一个定向开覆盖在D上有一个点有限加细.
通過介紹幾乎基一亞緊定義,研究瞭幾乎基一亞緊空間,得到如下結論:(1)若X是可數箇相對于X是幾乎基一亞緊的閉集的併,則X是幾乎基-亞緊的;(2)空間X是幾乎基一亞緊的,噹且僅噹它有一箇開基B,且|B|=w(X),和一箇稠密子集D∈X,使得對X的每一箇定嚮開覆蓋在D上有一箇點有限加細.
통과개소궤호기일아긴정의,연구료궤호기일아긴공간,득도여하결론:(1)약X시가수개상대우X시궤호기일아긴적폐집적병,칙X시궤호기-아긴적;(2)공간X시궤호기일아긴적,당차부당타유일개개기B,차|B|=w(X),화일개주밀자집D∈X,사득대X적매일개정향개복개재D상유일개점유한가세.
We introduce the notion of nearly base-metacompactness, mainly study nearly base- metacompactness of topological spaces. We prove the following: ( 1 ) If X is the countable union of closed nearly base-metacompaet sets relative to X, then X is nearly base-metacompact. (2) A space X is nearly base-metacompact if and only if it has an open base B with |B| = w(X) , and a dense set D X such that every directed open cover of X has a point-finite refinement by members of B on D .