Correction to: Adding a random or a Cohen real: topological consequences and the effect on Martin's axiom
Corrigendum to "Products of pseudoradial spaces".
Countable fan-tightness versus countable tightness
Countable tightness is compared to the stronger notion of countable fan-tightness. In particular, we prove that countable tightness is equivalent to countable fan-tightness in countably compact regular spaces, and that countable fan-tightness is preserved by pseudo-open compact mappings. We also discuss the behaviour of countable tightness and of countable fan-tightness under the product operation.
Countable Hausdorff spaces with countable weight
Covering of a space by nowhere dense sets