Section 34: Problem 1 Solution
Working problems is a crucial part of learning mathematics. No one can learn topology merely by poring over the definitions, theorems, and examples that are worked out in the text. One must work part of it out for oneself. To provide that opportunity is the purpose of the exercises.
James R. Munkres
was given before as an example of a space which is Hausdorff but not regular (
is closed but cannot be separated from
). It is also second-countable. Since it is not regular, it is not metrizable.