关于可数网的一些问题

主要解决了在正则空间中四种可数网的等价性问题,以及通过度量空间所给出的它们的刻画。

■_0-弱基及相关问题(英文)

证明在空间X中下列论述等价:(1)X有σ-离散的■0-弱基;(2)X有σ-局部有限的■0-弱基;(3)X是■0-弱第一可数的空间,■0-弱基是开、闭遗传的,点可数■0-弱基是cs*-网.并讨论■0-弱基,sn-网,cs-网以及cs*-网的关系.

Spaces with σ-locally Countable Weak Bases

In this paper, by msss_mappings, the relations between metric spaces and spaces with σ _locally countable cs_networks or spaces with σ _locally countable weak bases are established. These are some answers to Alexandroff’s problems.

On Point countable Sequential Neighborhood Networks

In this paper we prove that a space X with point countable sequential neighborhood network if and only if it is α 4 space with point countable cs network.

关于Lanev空间

本文给出非-空间的Lasnev空间的一个特征。作为它的推论,我们证明了一个Lasnev空间是一个?-空间当且仅当它具有点可数cs-网。