COMPACT SPACES REPRESENTABLE AS UNIONS OF NICE SUBSPACES

被引:4
|
作者
ISMAIL, M
SZYMANSKI, A
机构
[1] Department of Mathematics, Slippery Rock University, Slippery Rock
关键词
COMPACT; INITIALLY KAPPA-COMPACT; KAPPA-REFINABLE; (PSEUDO)CHARACTER; FILTER BASE; (DISCRETE) CONVERGENT SEQUENCE;
D O I
10.1016/0166-8641(94)90025-6
中图分类号
O29 [应用数学];
学科分类号
070104 ;
摘要
We present several results on compact Hausdorff spaces which can be represented as unions of nice subspaces. Some typical results are: If X is a compact Hausdorff space, and X = U(alpha < kappa)X(alpha), where each X(alpha) is kappa-refinable and PSI(X(alpha)) less-than-or-equal-to kappa, then (i) every nonempty G(kappa)-subset of X contains a point of character less-than-or-equal-to kappa, (ii) if x is-an-element-of X, chi(x, X) = mu > kappa and mu is regular, then there exists a discrete sequence {x(alpha): alpha < mu} in X such that x(alpha) --> x, (iii) if A is a nonclosed subset of X, then there exists a point x is-an-element-of X\A and a filter base F of subsets of A such that \F\ less-than-or-equal-to kappa and F --> x. We also show that if a compact Hausdorff space X is a union of countably many metrizable spaces, X has no isolated points and c(X) = omega0, then X is a compactification of the space of irrationals.
引用
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页码:287 / 298
页数:12
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