$\left\{e\right\}$ Closed Implies $T_0$ and Regular Topological Group
69652
Help understanding proof of every topological group is regular
10702
Show that $\left\{A\subset\Omega: A~\text{ is countable or }A^C\text{ is countable}\right\}$ is a $\sigma$-algebra
47680
Prove that the union of the interior of a set and the boundary of the set is the closure of the set
26256
Characterizing Dense Subgroups of the Reals
27661
The closed graph theorem in topology
122821
Is the following proof valid? About the closure of a subgroup, of a topological group, being again a subgroup
60208
Proof of property of abelian group
16512
Product of $T_1$ spaces is $T_1$
90599
Trouble with proving $A$ is an integrally closed domain $\Rightarrow$ $A[t]$ is integrally closed domain
72190
Topological proof on discrete topology where $X$ is infinite
52865
Topological Vector Space: $\dim Z\text{ finite}\implies Z\text{ closed}$
142145
strictly positive elements in $C^*$-algebra
150987
Showing that the product and metric topology on $\mathbb{R}^n$ are equivalent
158523
Topology: Proof that a finitely generated cone is closed
92064
A closed subset of an algebraic group which contains $e$ and is closed under taking products is a subgroup of $G$
102048
Closure of a compact set in Regular space $ X $
42108
Prove that $c_0$ is closed in $\ell^\infty$