Method/approach to show given set is closed
102117
Show that the domain is closed
56581
Possibility to object to closing?
99678
Is a sphere a closed set?
85225
The set of integers is not open or is open
153495
Continuous function does not map closed set to closed set
22803
Closing Streams in Java
70959
Prove that a set $E$ is closed iff it's complement $E^{c}$ is open
123498
Is "empty set" an element of a set?
21820
How to prove that a set is invariant?
111538
If $S \subseteq X$ is closed, is $f(S,r)$ necessarily closed?
116009
Proving that if a set is both open and closed then it is equal to the real numbers
91991
How do I prove that two closed sets are separable?
144383
The closure of a connected set in a topological space is connected
28604
Java socket API: How to tell if a connection has been closed?
55614
Prove that a set consisting of a sequence and its limit point is closed
61930
Intersection of Closed and Compact Set is Closed
46698
Showing a set is closed under inverses