具有特殊网σ-空间的研究(英文)

Research on σ-spaces with Special Nets

摘要: 给出了一个强σ-空间是闭PF-网空间的充要条件,并且证明如果X是强σ-空间,且 |X | b,则也是 LF-网空间,其中 b =min |F|:F在 , W≤ 中无界 .本文的结果部分回答了 Junnila与 Yajima所提出的公开问题.

Abstract: This paper gived a sufficient and necessary condition under which a σ-space is closed PF-netted and proved that if X is a strong σ-space with |X|b-,then X is LF-netted as well,where ■=min|F|:F is unbounded in(ωω,≤*,which is a partial answer to an open problem raised by Junnila and Yajima