Why $f\colon \mathbb{Z}_n^\times \to \mathbb{Z}_m^\times$ is surjective?
47709
If $n\mid m$ prove that the canonical surjection $\pi: \mathbb Z_m \rightarrow \mathbb Z_n$ is also surjective on units
35626
Is $(\mathbb{R}^2, lexicographic) \cong (\mathbb{R}, discrete)\times (\mathbb{R}, usual)$?
98507
$\text{Aut}(F)$ is isomorphic to the multiplicative group of all $n\times n$ matrices over $\mathbb Z$
115088
Surjective morphism of affine varieties and dimension
146306
A continuous surjective function from $(0,1]$ onto $[0,1]$
155266
Is $\exp:\overline{\mathbb{M}}_n\to\mathbb{M}_n$ injective?
46748
If $g \circ f$ is surjective, show that $f$ does not have to be surjective?
84114
Does there exist a surjective homomorphism from $(\mathbb R,+)$ to $(\mathbb Q,+)$ ?
126472
Surjective endomorphisms of uniserial modules
74453
Injective and Surjective Functions
13761
Automorphisms in $\mathbb{Z}_n$
53168
Surjective, Injective, Bijective Functions from $\mathbb Z$ to itself
132311
T$\mathbb{S}^{n} \times \mathbb{R}$ is diffeomorphic to $\mathbb{S}^{n}\times \mathbb{R}^{n+1}$
49833
Simple bijection $\mathbb N_0 \times \mathbb N_0 \to \mathbb N_0$
73047
Proving surjectivity of $\cos(z)$ and $\sin(z)$ and find all $z : \cos(z) \in \mathbb R$ and all $z: \sin(z) \in \mathbb R$
154754
Is $O_n$ isomorphic to $SO_n \times \{\pm I\}$?
97878
Are there uncountably many surjections from $\mathbb N$ to $\mathbb N$?