$GL_n(R)$ is open set in $M_n(R)$
110217
$GL(n,K)$ is open in $M(n,K)$
66866
Algebraic dual of $\mathbb{R}^{\mathbb{N}}$
67279
Is the union of finitely many open sets in an omega-cover contained within some member of the cover?
78263
Prove $GL_n(\Bbb{R})/SL_n(\Bbb{R}) \cong \Bbb{R}^\times$
84437
Prove that the projection $p_i$ from the product space $X_I S_i \tau$ into $S_i \tau_i$ is open for each $i \in I$
6491
Not every open set in $\mathbb{R}^n$, for $n\geq2$, is a disjoint union of countable open balls.
3296
Proof That $\mathbb{R} \setminus \mathbb{Q}$ Is Not an $F_{\sigma}$ Set
50344
What is the closure of an open ball $B_X(\mathbf{a},r)$ in $X=\mathbb{R}^n$?
105610
Normalizer of upper triangular group in ${\rm GL}(n,F)$
149317
An open subset of $\mathbb{R}$ is an at-most-countable union of disjoint open intervals
16602
Proving $M_n(I)\lhd M_n(R)$ and proofs about ideal rings.
110957
No non-trivial clopen sets in $\mathbb{R}$? How to give a direct proof?
102284
$GL(n,\mathbb R)/SL(n,\mathbb R)$ is isomophic to $\mathbb R^\times$
126463
Can open sets and closed sets of $\mathbb{R}^n$ be homeomorphic?
23037
Computing the order of $\mathrm{SL}_2(\mathbb F_p)$ as the kernel of $\mathrm{GL}_2(\mathbb F_p)$
101504
An open ball is an open set
69542
Why do the $n \times n$ non-singular matrices form an "open" set?