Proving $\mathbb{N} \times \mathbb{N} \cong \mathbb{N}$ when $\mathbb{N}$ includes $0$
54761
Inverting the Cantor pairing function
75604
Proof that $\partial(A\times B) = ((\partial A)\times B)\cup (A\times(\partial B))$
35948
How to prove $D^n/S^{n-1}\cong S^n$?
58033
$G\times H\cong G$ with $H$ non-trivial
139833
Prove that $\gcd(M, N)\times \mbox{lcm}(M, N) = M \times N$.
127720
Prove that $\bigcup_{n \in \Bbb{N}} [1/n,1] = (0,1]$.
157840
Is it true that $(R\times S)[G]\cong R[G]\times S[G]$?
115876
$D_6 \cong D_3\times \mathbb Z_2$
54406
Is $\mathbb Q \times \mathbb Q $ a denumerable set?
67772
How to find $k$ such that $(\mathbb{Z} \times \mathbb{Z})/ \langle (m,n)\rangle \cong \mathbb{Z} \times \mathbb{Z}_k$
6161
The cartesian product $\mathbb{N} \times \mathbb{N}$ is countable
39231
Construct a bijection between $\mathbb{Z}^+\times \mathbb{Z}^+$ and $\mathbb{Z}^+$
140471
Is $ G \cong G/N \times N$?
88155
Show that $[0, 1)\times[0, 1)$ is homeomorphic to $[0, 1]\times[0, 1)$ but not to $[0, 1]\times[0, 1]$.
109710
Bijection between $\mathbb N \times \mathbb N$ and $\mathbb N$
118452
how to prove $\mathbb Z_n$ has divisors of zero if and only if $n$ is not prime
120642
Let $g : \Bbb N \times \Bbb N \to\Bbb N \times \Bbb N$ defined as $g(m,n) = (m + n,m - n)$