Prove der (A) is closed
66293
$der(\{x\})$ is closed and $x\in der(der(A))$
148992
A finite set is closed
116009
Proving that if a set is both open and closed then it is equal to the real numbers
42108
Prove that $c_0$ is closed in $\ell^\infty$
158523
Topology: Proof that a finitely generated cone is closed
157939
prove that a graph is one-ended
11557
How to prove $\det(e^A) = e^{\operatorname{tr}(A)}$?
111515
Proving that $-a=(-1)\cdot a$
102170
Showing a Sequence and its Limit are Closed
90599
Trouble with proving $A$ is an integrally closed domain $\Rightarrow$ $A[t]$ is integrally closed domain
108734
$T$ is continuous if and only if $\ker T$ is closed
130299
Prove that if a function $f: X\to Y$ continuous then its graph is closed
78471
Closure of $\{\frac{1}{n}\}:=M$
47680
Prove that the union of the interior of a set and the boundary of the set is the closure of the set
110744
How to prove that a compact set in a Hausdorff topological space is closed?
8414
Proof verification: Set of partial limits of a sequence is closed
136851
Proof that the set of subsequential limits is closed