Extension properties and the Niemytzki plane

Haruto Ohta
2000 Applied General Topology  
<p>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.</p>
doi:10.4995/agt.2000.3023 fatcat:c2hs4glnkzfxfb5f7u6bhwdnsq