Cardinal Invariants for the $G_\delta $ topology
Tom 156 / 2019
Colloquium Mathematicum 156 (2019), 123-133
MSC: Primary 54A25; Secondary 54D20, 54G20.
DOI: 10.4064/cm7349-6-2018
Opublikowany online: 11 January 2019
Streszczenie
We prove upper bounds for the spread, the Lindelöf number and the weak Lindelöf number of the $G_\delta $ topology on a topological space, and apply a few of our bounds to give a short proof to a recent result of Juhász and van Mill regarding the cardinality of a $\sigma $-countably tight homogeneous compactum.