Prove that $A$ is a compact subset of $M_3(\Bbb R) \cong \Bbb R^9$.
86309
Whether the set $A$ is a compact subset of $M_3(\Bbb R)$.
114916
$\mathbb Z_{mn}$ isomorphic to $\mathbb Z_m\times\mathbb Z_n$ whenever $m$ and $n$ are coprime
6896
If $A/I \cong A/J$ as rings and $I\subseteq J,$ then $I=J.$
80180
Discrete and compact subset must be finite
122330
Prove that there exists some $c\in(-3,3)$ such that$ \ \ g(c) \cdot g''(c)<0$.
22854
Let $A , B\subseteq\mathbb{R}$. If $A$ is closed and $B$ is compact, is $A\cdot B$ closed?
140446
Prove that $A \smallsetminus (A \smallsetminus B) = A \cap B$
104855
Prove that $N \subset Z(G)$
48783
Prove that the sum of two compact sets in $\mathbb R^n$ is compact.
75614
Proving that $n|m\implies f_n|f_m$
4648
Proving that $\mathbb{Z}_m\oplus \mathbb{Z}_n \cong \mathbb{Z}_d\oplus \mathbb{Z}_l $ as groups, where $l=\mathrm{lcm}(m,n)$ and $d=\gcd(m,n)$
83311
Compactness of $A:=${$f \in C[0,1], |f|_\infty \le K, |f'|_\infty \le M$}
78263
Prove $GL_n(\Bbb{R})/SL_n(\Bbb{R}) \cong \Bbb{R}^\times$
83009
Showing that $R(x)$ is a proper subset of $R((x))$ if $R$ is a field
63529
How to show that this set is compact in $\ell^2$
51914
Show that $S$ is compact.
140570
Suppose $E\subseteq\mathbb{R}$ is closed and $K\subseteq\mathbb{R}$ is compact. Show that every open cover of $E\cap K$ has a finite subcover