2 papers
math.GN2022
On symmetrizability and perfectness of second-countable spaces
Iryna Banakh, Taras Banakh, Lidiya Bazylevych
A symmetrizability criterion of Arhangelskii implies that a second-countable Hausdorff space is symmetrizable if and only if it is perfect. We present an example of a non-symmetriz…
math.GN2022
-spaces, perfect spaces and related cardinal characteristics of the continuum
Taras Banakh, Lidiya Bazylevych
A topological space is called a -space if every subset of is of type in . For let be the smallest cardinality of a second-counta…