Original scientific paper
APPLICATIONS OF Θ-CLOSED AND U-CLOSED SETS
Ivan Lončar
; Faculty of Organization and Informatics, University of Zagreb, Varaždin, Croatia
Abstract
Fop every Hausdorff space X the spaces XΘ and Xu are introduced. If X is H-closed (Urysohn-closed) then XΘ (Xu) is compact T1-space. If f: X->Y is a mapping, then there exist the mappings fΘ:XΘ->YΘ and fu: Xu->Yu. We say that f : X->Y is a Θ-closed (u-closed) mapping if fΘ (fu) is a closed mapping. If X and Y are H-closed (Urysohn-closed) and f: X->Y is the HJ-mapping, then fΘ(fu) is Θ-closed (u-closed) Let X = {Xα , fαβ ,A } be an inverse system of the H-closed (Urysohn-closed) spaces Xα and the Θ-closed (u-closed) mappings fαβ . If Xα are non-empty spaces, then X = limX ≠ Ø
Keywords
Hrčak ID:
80828
URI
Publication date:
14.12.1984.
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