Injective hull of $\mathbb{ Z}_n$
138258
What is the injective envelope of $\mathbb{Z}/n\mathbb{Z}$?
42412
Singular homology $S^{n}$ with rational coefficients
124864
A not free $\mathbb{Z}$-module
130937
Embeddings of finite groups into $\mathrm{GL}_n(\mathbb{Z})$
116943
Proof for maximal ideals in $\mathbb{Z}[x]$
123742
Proving connectedness of the $n$-sphere
7303
How many idempotent elements does the ring ${\bf Z}_n$ contain?
136804
Computing $\mathrm{Hom}(\mathbb Z_n,\mathbb Z_m)$ as $\mathbb Z$-module
93681
Integral closure of $\mathbb{Z}$ in $\mathbb{C}$ is not finitely generated as a $\mathbb{Z}$-module?
90192
Kernel and Image of a group homomorphism
30456
The number of $2 × 2$ invertible matrices with entries from field $\mathbb{Z}_p$
133019
Nilpotent elements in $\mathbb Z_n$
145752
Aut $\mathbb Z_p\simeq \mathbb Z_{p-1}$
45991
Why $f\colon \mathbb{Z}_n^\times \to \mathbb{Z}_m^\times$ is surjective?
28934
Presentation of SL$(n,\mathbb{Z}_p)$
152457
$\mathbb Z_n$ is semisimple iff $n$ is square free
126930
Finding all group homomorphisms of $S_n\to\mathbb{C}^*$ and $A_n\to\mathbb{C}^*$