If $L$ commutes with all isomorphisms of $\mathbb{F}_2^n$, is $L=\lambda I$ for some $\lambda$?
4280
A linear operator commuting with all such operators is a scalar multiple of the identity.
121449
An isomorphism from $GL_{2}(\mathbb{F_{2}})$ to $S_{3}$
51695
Finding all homomorphisms between $\mathbb{Z}/m\mathbb{Z}$ and $\mathbb{Z}/n\mathbb{Z}$
118354
Epimorphism and Monomorphism = Isomorphism?
55900
Is there a ring homomorphism $M_2(\mathbb Z)\to \mathbb Z$?
67374
Is it true that $\mathbb{R}$ and $\mathbb{R}^2$ are isomorphic as abelian groups?
154754
Is $O_n$ isomorphic to $SO_n \times \{\pm I\}$?
87265
If $(A-\lambda{I})$ is $\lambda$-equivalent to $(B-\lambda{I})$ then $A$ is similar to $B$
95806
Proving commutativity of convolution $(f \ast g)(x) = (g \ast f)(x)$
13761
Automorphisms in $\mathbb{Z}_n$
26661
Ring homomorphisms from $\mathbb{Z}_n$ to $\mathbb{Z}_m$
109610
Is $\mathbb{R}[X]/(P)$ isomorphic to $\mathbb C$ for every irreducible polynomial $P$ of degree $2?$
126930
Finding all group homomorphisms of $S_n\to\mathbb{C}^*$ and $A_n\to\mathbb{C}^*$
82474
Isometries of $\mathbb{R}^n$
116594
Finite fields are isomorphic
33702
Is this an isomorphism possible?
68514
Let $M$ be a smooth manifold and let $N$ be a manifold with boundary. If $dF_{p}$ is an isomorphism, then $F\left(p\right)\in\mbox{int}M $.