首页 | 本学科首页   官方微博 | 高级检索  
     


Resolvability of spaces having small spread or extent
Authors:Istvá  n Juhá  sz,Lajos Soukup
Affiliation:a Alfréd Rényi Institute of Mathematics, Hungary
b Eötvös University of Budapest, Hungary
Abstract:In a recent paper O. Pavlov proved the following two interesting resolvability results:
(1)
If a T1-space X satisfies Δ(X)>ps(X) then X is maximally resolvable.
(2)
If a T3-space X satisfies Δ(X)>pe(X) then X is ω-resolvable.
Here ps(X) (pe(X)) denotes the smallest successor cardinal such that X has no discrete (closed discrete) subset of that size and Δ(X) is the smallest cardinality of a non-empty open set in X.In this note we improve (1) by showing that Δ(X)>ps(X) can be relaxed to Δ(X)?ps(X), actually for an arbitrary topological space X. In particular, if X is any space of countable spread with Δ(X)>ω then X is maximally resolvable.The question if an analogous improvement of (2) is valid remains open, but we present a proof of (2) that is simpler than Pavlov's.
Keywords:54A25   54B05
本文献已被 ScienceDirect 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号