Mathematica Bohemica, Vol. 146, No. 4, pp. 457-469, 2021
The Niemytzki plane is $\varkappa$-metrizable
Wojciech Bielas, Andrzej Kucharski, Szymon Plewik
Received December 11, 2019. Published online February 10, 2021.
Abstract: We prove that the Niemytzki plane is $\varkappa$-metrizable and we try to explain the differences between the concepts of a stratifiable space and a $\varkappa$-metrizable space. Also, we give a characterisation of $\varkappa$-metrizable spaces which is modelled on the version described by Chigogidze.
Keywords: stratifiable space; $\varkappa$-metrizable space; Niemytzki plane; Sorgenfrey line