Closure of an open ball is a subset of the closed ball
43248
Closure of a Ball is Contained in Closed Ball (usual metric)
116009
Proving that if a set is both open and closed then it is equal to the real numbers
8015
Compact set plus a closed set is a closed set
114608
Proof concerning regular space: there exist a closed set contained in any open set containing $x$
46698
Showing a set is closed under inverses
117508
Prove that the closed unit ball of $L^2[a,b]$ is closed in $L^1[a,b]$
127173
Closed subset of compact set is compact
138202
Every open set in $\mathbb{R}$ is a countable union of closed sets
42698
Set of limit points of a subset of a Hausdorff space is closed.
118765
A topological space is locally compact then here is an open base at each point has all of its set with compact closure
146146
Proof that a closed subset of a compact space is a compact space
102048
Closure of a compact set in Regular space $ X $
3896
A closed set in $(A, \mathcal T_A)$ that is not closed in $(X, \mathcal T)$
10477
Finding the closure of A=$\mathbb Q \cap [0,1]$.
106534
"Closed subsets of compact space are compact" with an alternative definition of covering
24050
Characterization of the Closure of a Set
59654
Show that in a discrete metric space, every subset is both open and closed.