PSEUDOLINDELOF SPACES AND HEWITT REALCOMPACTIFICATION OF PRODUCTS
한국수학교육학회지시리즈B:순수및응용수학 / Journal of the Korean Society of Mathematical Education Series B: Theoretical Mathematics and Pedagogical Mathematics, (P)3059-0604; (E)3059-1309
1999, v.6 no.1, pp.39-45
Kim, Chang-Il
(Department of Mathematics Education, College of Education, Dankook University)
Kim, Chang-Il.
(1999). PSEUDOLINDELOF SPACES AND HEWITT REALCOMPACTIFICATION OF PRODUCTS, 6(1), 39-45.
Abstract
The concept of pseudoLindelof spaces is introduced. It is shown that the followings are equivalent: (a) for any two disjoint zero-sets in X, at least one of them is Lindelof, (b) $\mid$vX{\;}-{\;}X$\mid${\leq}{\;}1$, and (c) for any space T with $X{\;}{\subseteq}{\;}T$, there is an embedding $f{\;}:{\;}vX{\;}{\rightarrow}{\;}vT$ such that f(x) = x for all $x{\;}{\in}{\;}X$ and that if $X{\;}{\times}{\;}Y$ is a z-embedded pseudoLindelof subspace of $vX{\;}{\times}{\;}vY,{\;}then{\;}v(X{\;}{\times}{\;}Y){\;}={\;}vX{\;}{\times}{\;}vY$.
- keywords
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z-closed map,
C-embedding,
realcompactification,
P-space