Title of article :
What is a first countable space?
Author/Authors :
Gutierres، نويسنده , , Gonçalo، نويسنده ,
Issue Information :
دوماهنامه با شماره پیاپی سال 2006
Abstract :
The definition of first countable space is standard and its meaning is very clear. But is that the case in the absence of the Axiom of Choice? The answer is negative because there are at least three choice-free versions of first countability. And, most likely, the usual definition does not correspond to what we want to be a first countable space. The three definitions as well as other characterizations of first countability are presented and it is discussed under which set-theoretic conditions they remain equivalent.
Keywords :
First countable space , AXIOM OF CHOICE
Journal title :
Topology and its Applications
Journal title :
Topology and its Applications