Section 28: 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
Interesting.
has no limit point (if
has a coordinate in
then a small enough ball does not contain any other point in
, otherwise the distance to any point in
is either 0 or 1).