How to prove that this set is closed.
158523
Topology: Proof that a finitely generated cone is closed
121304
Is the set of polynomials of degree less than or equal to $n$ closed?
157603
Continuity $\iff$ Preimage is closed whenever set is closed
70959
Prove that a set $E$ is closed iff it's complement $E^{c}$ is open
13848
Showing that if a subset of a complete metric space is closed, it is also complete
106944
Is the set defined by y=sin(1/x) open or closed?
143105
Show that, for every real number a, the set {$x ∈ S | f(x) ≤ a$} is a closed subset of $\mathbb R^d$
60359
Proving that these two sets are denumerable.
92774
Prove that a linear subspace of $C([0,1])$ is closed
88904
Help with a proof. Countable sets.
68994
Countable closed sets
77286
Proving set theory question
152193
The intersection of a closure with an open set
136851
Proof that the set of subsequential limits is closed
95244
Prove that a finite union of closed sets is also closed
79424
Don't understand proof that interior of a set is open
42698
Set of limit points of a subset of a Hausdorff space is closed.