Open AccessExtension properties and the Niemytzki plane
Author(s) -
Haruto Ohta
Publication year - 2000
Publication title -
applied general topology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.638
H-Index - 13
eISSN - 1989-4147
pISSN - 1576-9402
DOI - 10.4995/agt.2000.3023
Subject(s) - mathematics , embedding , extension (predicate logic) , plane (geometry) , zero (linguistics) , set (abstract data type) , combinatorics , discrete mathematics , geometry , computer science , artificial intelligence , programming language , linguistics , philosophy
The first part of the paper is a brief survey on recent topics concerning the relationship between C*-embedding and C-embedding for closed subsets. The second part studies extension properties of the Niemytzki plane NO. A zero-set, z-; C*-, and P-embedded subsets of NP are determined. Finally, we prove that every C*-embedded subset of NP is a P-embedded zero-set, which answers a problem raised in the first part