对A.Hajnal和I.Juhasz问题的讨论

A Note on the Problom Proposed by A.Hajnal and J.Juhasz.

用部分子空间的基数函数值来估计整体空间的基数函数值,这是一个有趣的问题。M.G.Tkacenko曾经证明了下面定理: 定理1(见[1]):设X是非T_3空间,如果X满足条件:对任意Z?X,|Z|≤k(k>ω),有W(Z)<k,则W(X)<k。

In this paper we fred that the problem proposed by A. H. ajnal and I. Juhasz is true if topological space X is T_2. And under some set theoretic assumptions generalized problem is researched.