$\phi : A^n \to A^n $ be a surjective $A$-linear map then $\phi$ is injective as well.
45576
A surjective homomorphism between finite free modules of the same rank
21391
Proving Functions are Surjective
63845
Diffeomorphism $f:U\to V$ then $Df:\mathbb{R^n}\to\mathbb{R^m}$ will be linear isomorphism hence $n=m$
97605
Let $f$ be a surjective homomorphism. Prove that $\ker(f)$ is a maximal ideal
93102
prove that $f:X\rightarrow Y$ is surjective if and only if $f(f^{-1}(C))=C$
59724
Proving that $x_n\to L$ implies $|x_n|\to |L|$, and what about the converse?
44065
If $B$ is finitely generated as a $k$-algebra, and $\phi:A\to B$ is a $k$-algebra map, is $\phi^{-1}(M)$ maximal for any maximal $M\subset B$?
133083
Injectivity and surjectivity of a recursive function
93964
Proving that $f$ is a bijection from $N$x$N$ to $N$.
30049
If $T^m$ is diagonalizable for a $m\in\mathbb N$, then $T$ is diagonalizable.
97878
Are there uncountably many surjections from $\mathbb N$ to $\mathbb N$?
41846
$(\mathbb{R}^n,\|\cdot\|_{p})$ is isometrically isomorphic to $(\mathbb{R}^n,\|\cdot\|_{q})$ iff $p=q,$
7890
Prove the map $\Phi:G\to\operatorname{Aut}G$ with $g\mapsto (x\mapsto g^{-1}xg)$ is an homomorphism.
93923
No surjective bounded linear map from $\ell^2(\mathbf{N})$ to $\ell^1(\mathbf{N})$
45991
Why $f\colon \mathbb{Z}_n^\times \to \mathbb{Z}_m^\times$ is surjective?
49953
Proving that a function from $N\times N$ to $N$ is bijective.
116732
Proving that a continuous map is surjective