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  • P-ISSN1226-0657
  • E-ISSN2287-6081
  • KCI

AN EXTENSION WHICH IS A WEAKLY LINDELÖFF SPACE

Journal of the Korean Society of Mathematical Education Series B: The Pure and Applied Mathematics / Journal of the Korean Society of Mathematical Education Series B: The Pure and Applied Mathematics, (P)1226-0657; (E)2287-6081
2012, v.19 no.3, pp.273-279
https://doi.org/10.7468/jksmeb.2012.19.3.273
Yun, Yong-Sik
Kim, Chang-Il

Abstract

In this paper, we construct an extension (<TEX>$kX$</TEX>, <TEX>$k_X$</TEX>) of a space X such that <TEX>$kX$</TEX> is a weakly Lindel<TEX>$\ddot{o}$</TEX>ff space and for any continuous map <TEX>$f:X{\rightarrow}Y$</TEX>, there is a continuous map <TEX>$g:kX{\rightarrow}kY$</TEX> such that <TEX>$g|x=f$</TEX>. Moreover, we show that <TEX>${\upsilon}X$</TEX> is Lindel<TEX>$\ddot{o}$</TEX>ff if and only if <TEX>$kX={\upsilon}X$</TEX> and that for any P'-space X which is weakly Lindel<TEX>$\ddot{o}$</TEX>ff, <TEX>$kX={\upsilon}X$</TEX>.

keywords
filter, realcompactification, weakly Lindel<tex> $\ddot{o}$</tex>ff space

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Journal of the Korean Society of Mathematical Education Series B: The Pure and Applied Mathematics